Dr Shiming Zhang is an Assistant Professor of Bioelectronics in the Department of Electrical and Computer Engineering and the Principal Investigator of the Wearable, Intelligent and Soft Electronics Laboratory (HKU-WISE). He is also an affiliated faculty member in the School of Biomedical Engineering. He received his PhD from the Department of Chemical Engineering at the University of Montreal, Canada, and completed his postdoctoral training in the Department of Bioengineering at the University of California, Los Angeles (UCLA).
His research focuses on developing tissue-compatible organic bioelectronics, with particular emphasis on the charge-transport mechanisms of organic mixed ionic-electronic semiconductors, the design of novel mixed-conducting devices and systems, and the application of these technologies in fields such as medical electronics and biological computing. Among his representative achievements is the "3D hydrogel transistor" technology developed in 2025. Featured on the cover of Science, the work was recognised as "pushing the limits of technology and redefining the boundary between biology and electronics," and was selected as one of China's Top Ten Scientific Achievements of 2025 by the Science and Technology Review of the China Association for Science and Technology.
He currently serves as an international editorial board member of Advanced Electronic Materials and Advanced Biosensors, and as a committee member of the Biomedical Devices Technical Committee of the IEEE Electron Devices Society.
Design principles for π-conjugated hydrogel semiconductors
Hao Huang, Jing Bai, Silan Zhang, Binbin Cui, Xiaonan Chen, Shilei Dai, Xiang Meng, Ngai Wong, George G. Malliaras & Shiming Zhang
HKU Engineering Researchers Contribute Design Principles for Hydrogel Semiconductors towards Tissue-Integrable Medical Electronics
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Following the publication of the world's first three-dimensional hydrogel transistor on the cover of Science in November 2025, which attracted widespread attention across the scientific community, the Wearable, Intelligent, Soft Electronics research group at The University of Hong Kong (HKU-WISE) has once again earned recognition from a top international journal. The team has published a review article in Nature Materials, titled "Design Principles for π-Conjugated Hydrogel Semiconductors." It is the first paper to systematically trace the development of this emerging field, providing a guiding framework for future research.
Silicon-based transistors are the cornerstone of modern electronic technology, offering powerful signal amplification and computing capabilities. However, because they differ from biological systems in mechanical properties, charge-carrier characteristics, and dimensionality, silicon devices struggle to integrate seamlessly with human tissue across soft, wet interfaces. As a result, their inherent advantages remain difficult to apply in the field of medical electronics, constraining progress in related technologies.
Invented at HKU and emerging from the intersection of organic bioelectronics, hydrogels, and electrochemistry, hydrogel transistor technology organically combines the tissue compatibility of hydrogels with the functionality of semiconductors, overcoming this integration barrier at the technical level.
The review explains that the core of a π-conjugated hydrogel semiconductor lies in embedding π-conjugated organic mixed ionic-electronic conductors within a water-rich, three-dimensional hydrogel network. Within a tissue-soft environment, these materials simultaneously achieve ion transport, electron transport, and ion-electron conversion, upgrading hydrogels from passive conductive materials into semiconductors capable of switching and signal amplification.
The article distils the field's central challenge into a single question: how to simultaneously make ions move quickly, electrons flow freely, and the conversion between the two highly efficient within a tissue-like, soft, 3D hydrogel. It systematically introduces the corresponding methodologies, and calls for the establishment of unified evaluation and design standards covering ion-electron transport, coupling efficiency, and stability, while proposing a concrete implementation framework.
The article also points out that the field remains in its early stages. Biocompatibility, long-term stability, the coordinated realisation of multiple performance parameters, and in-body safety all require systematic validation. Overcoming these technical challenges could revolutionise wearable health monitoring, implantable medicine, soft bioelectronics, brain-inspired computing, and real-time studies of biological processes, among many other directions.
The research was supported by a Young Collaborative Research Grant (YCRG) from the Hong Kong Research Grants Council. This series of achievements marks a key step forward in merging electronics with biology, opening a new chapter for the future of bioelectronics.
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