The HKU Mechanical Engineering team developed an electroconductive hydrogel for

Synthetic hydrogels hold great promise in tissue repair, drug delivery, medical implants and many other applications. Functionalized hydrogels with electrically conductive components can be used in bioelectronic devices for cardiac or neural interfaces, for applications such as nerve prosthetics, heart patches and electronic skins.

A research team led by Dr Lizhi Xu from the Department of Mechanical Engineering at the Faculty of Engineering at the University of Hong Kong (HKU) recently developed a new type of electroconductive hydrogel with outstanding mechanical strength and manufacturability, creating opportunities for the engineering of various bioelectronic devices.

Innovations have been published in Nature Communications in the article entitled “Hybrid assembly of polymer nanofiber networks for strong and electronically conductive hydrogels”.

Synthetic hydrogels are water-rich polymeric materials that mimic biological soft tissue. They are soft, porous and biocompatible, enabling a physical interface between natural biological tissues and advanced biomedical tools. In particular, electroconductive hydrogels have attracted extensive research attention, as they can be used in bioelectronic devices for cardiac or neural interfaces.

“Existing hydrogels are mechanically weak and difficult to fabricate, which limits their practical utility. We use a unique micro-scaffold for the synthesis of conductive hydrogels. The composite architecture provides a combination of properties not accessible to other hydrogels, which is very important for realistic applications in bioelectronic devices,” said Dr Xu.

In the new hydrogel developed by Dr Xu’s team, a network of 3D nanofibers is used as a template to guide the assembly of conducting polymers (such as polypyrrole). The high connectivity of the nanofibers provides structural resistance and an effective pathway for electron conduction.

“For potential biomedical applications, devices need to withstand repetitive mechanical loads associated with body movements. In this case, the mechanical toughness of the material will be very important.” Dr. Xu explained.

The resulting material developed by the team contains 80% water by weight, while at the same time exhibiting a high electrical conductivity of ~80 S/cm and a mechanical strength of ~9.4 MPa.

“This conductive hydrogel is easy to make. One can pattern them into arrays of electrodes, interconnects and biosensors, enabling functional systems such as wearable health monitors or cardiac tissue engineering platforms.” Dr. Xu said.

“This opens up opportunities for many advanced medical devices in the future, such as neural prosthetics, heart patches, e-skins and so on.” he added.

Dr Xu and his research team previously created a new type of hydrogel that mimics tendons, exhibiting outstanding mechanical properties that closely resemble those of natural tendons, along with a variety of functions that are especially suitable for biomedical applications.
(press release: https://www.hku.hk/press/news_detail_26045.html)

Link to paper “Hybrid assembly of polymer nanofiber networks for strong and electronically conductive hydrogels”: https://www.nature.com/articles/s41467-023-36438-8

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