Recently, Ph.D. student Hao Liu from BEBC published a paper on the international top journal Small (IF 9.598) as the first author with the title of “Biofriendly, Stretchable, and Reusable Hydrogel Electronics as Wearable Force Sensors” under the joint guidance of Prof. Tianjian Lu, Prof. Xu Feng and Associate Professor Li Fei. This research paper is also presented as the cover story.

Flexible electronics are light, soft, stretchable and can be attached to skin, which allow for wearable electrophysiological signals monitoring and a good user experience, thus become a hot research field of biomedical engineering in recent years. The realization of flexible electronic functions relies on the use of flexible substrate materials. Although the widely used silicon-based materials (such as polydimethylsiloxane, etc.) exhibit good mechanical ductility, their lack of biocompatibility and mismatched mechanical properties with human skin will discomfort or even cause inflammation to users in the long-term wear, which greatly affecting the user experience. Therefore, a substrate material owns both biocompatibility and suitable mechanical ductility is yet to be discovered. The emergence of highly biocompatible, mechanically controllable hydrogel materials has brought the possibility of solving this problem. Based on the fruitful research results of the long-term use of porous biomaterials for tissue remodeling and targeted drug delivery, Hao Liu proposed a method for preparing user-friendly and reusable flexible electrons using hydrogel materials. In this study, a soft stretchable hydrogel material was used as a substrate, and a three-dimensional spiral passage was prepared in the hydrogel by templating where liquid metal (EGaIn) was filled as the conductive component.

Thanks to the uniform distribution of three-dimensional spiral under stress and the conformation of liquid conductive material, the flexible hydrogel electron exhibits good functional stability and great prospects in wearable strain sensing and pressure sensing. Moreover, because the excellent swelling properties of hydrogel, it can be rehydrated after dehydration and atrophy. Thus even the dehydrated, functionally disabled flexible hydrogel electrons can be functionally resuscitated by simply immersing in water, providing a viable solution to solve the large amount of e-waste problems worldwide.

Co-authors of this paper include Ph.D. student Moxiao Li , Prof. Tianjian Lu, Prof. Feng Xu and Associate Professor Li Fei. Hao Liu also thanked Associate Professor Huang Guoyou for his inspiration and help during the experimental design process. In addition, as an Arsenal fan, Hao Liu also hopes to pay tribute to the former coach of Mr. Wenger, who has just stepped down after the end of the season.