New tendon-mimetic hydrogel developed with outstanding mechanical properties and multifunctionalities

Clinical medicine faces a major challenge in repairing or replacing injured tendons and other load-bearing tissues. Natural tendons are water-rich tissues with exceptional mechanical strength and durability, thanks to their microscale structures comprising stiff collagen fibrils interlaced with soft water-retaining biopolymers.

Efforts have been made in the past few decades to use synthetic hydrogels, a class of water-rich materials consisting of polymer networks, to replicate the structures and properties of natural tendons. However, synthetic hydrogels are usually weak and brittle, making it challenging to match the mechanical properties of natural tendons. If this mismatch can be resolved, it would enable crucial applications in tissue repair, biomedical robots, implantable devices, and many other technologies.

A team of researchers led by Dr. Lizhi Xu from the Department of Mechanical Engineering in the Faculty of Engineering at the University of Hong Kong (HKU) has developed a novel tendon-mimetic hydrogel with exceptional mechanical properties and multifunctionalities for biomedical applications.

The research, titled “Multifunctional tendon-mimetic hydrogels,” was published in Science Advances and featured in Nature as a Research Highlight.

In this study, the researchers mixed aramid nanofibers derived from Kevlar, a polymer material used in bullet-proof vests and helmets, with polyvinyl alcohol, another synthetic polymer, to construct the tendon-mimetic hydrogels. By applying tensile stress during the fabrication process, the aramid nanofibers aligned with each other according to the direction of stretching, resulting in an anisotropic network that mimics the structural features of natural tendons.

The stiff nanofibers’ interactions with soft polymers further confer high mechanical toughness on the composites. Despite consisting of 60% water, the hydrogel exhibited an exceptional Young’s modulus of ~1 GPa and strength of ~80 MPa, surpassing other synthetic hydrogels by several orders of magnitude. The hydrogel’s surface can also be functionalized to direct cell behavior or integrate with soft bioelectronic sensors.

Dr. Xu stated, “We developed a biomimetic materials platform for advanced biomedical applications. The materials building blocks captured many structural features of natural tendons, leading to amazing properties that are inaccessible with other synthetic hydrogels.” She added that “these hydrogels are not only mechanically strong but also functionalized with bioactive molecules and soft electronic sensors, providing critical capabilities for tissue repair and implantable medical devices.

Source: The University of Hong Kong

Leave a Comment