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Our research aims to develop next-generation tissue-like soft materials/devices/systems for broad bioelectronic applications. We focus on PEDOT:PSS-based: 1) tissue-like soft organic bioelectronics; and 2) tissue-like soft hydrogel bioelectronics. This is because PEDOT:PSS is a typical organic mixed ion-electron conductor (OMIEC), and is the “silicon” material for soft bioelectronic applications considering its overall properties at large. We pursue fundamental research and engineering in this direction to solve the community’s most difficult challenges in designing, assembling, and interfacing PEDOT:PSS bioelectronics for medicine and biological systems. In doing so, we create new knowledge and push the boundaries of the discipline.

Research work in our laboratory is generously supported by:

  • RGC CRF (YCRG) 2023/24 (PC)
  • RGC German/Hong Kong Joint Funding Scheme 2022/23 (PI)
  • RGC GRF 2022/23 (PI)
  • RGC Postdoctoral Fellowship Scheme (PDFS) 2022/2023 (Primary Supervisor)
  • HKSI SRFS 2022/2023 (Co-PI)
  • RGC TRS 2022/2023 (Co-I)
  • ITF MOST-ITC 2021/2022 (PI)
  • SZSTI (Type C) 2021/2022 (PI)
  • Seed Funding for Strategic Interdisciplinary Research Scheme (SIRS), HKU 2022 (PI)
  • Small Equipment Grant, HKU 2021 (PI)
  • Innovation Wing Two Research Fund, HKU 2021 (PI)

PC for Project Coordinator; PI for Principal Investigator; Co-I for Co-Investigator

1. Hydrogel engineering for tissue-integratable biosensing and biocomputing

Hydrogel electrodes: Hydrogels are water-rich materials that are favorable of making commercial medical electrodes to interface with soft tissues.  However, the current hydrogel electrodes suffer from limited stretchability and dehydration issues that impedes long-term use. Here, we develop skin-conformable hydrogel electrodes with high-stretchability and good water-retention ability by developing multi-network composite hydrogel materials. Read more: Advanced Materials, InfoMat.

Funded by: RGC Collaborative Research Fund (CRF).

Semiconducting hydrogel transistors: The realization of hydrogel-based transistors holds significant value for developing tissue-integratable biologics. However, its development presents challenges, primarily due to the thin-film nature of semiconductors, which are generally less than 1 micrometer in thickness. In contrast, hydrogels have greater thicknesses and struggle to achieve good semiconductor properties. Here, we develop hydrogel-transistors by developing nanocomposite semiconducting hydrogel materials that able to maintain good semiconductor behavior at extremely thick thicknesses, e.g., 100 um, which unlocks their potential for tissue-integratable biosensing and biocomputing applications.  Read more: Advanced Materials, MRS presentation.

Self-healing semiconducting hydrogel: Materials able to heal damage, like the skin, are highly desirable to improve lifetime of tissue-like devices. However, self-healing are rarely observed in conductors with thin thicknesses. Using semiconducting polymers, we developed thin film hydrogel conductors that can realize extremely fast healing (< 0.1 second), at extremely thin thickness (< 1 um),   while maintaining a good semiconductor property.  Here, we use these unique semiconducting hydrogels to develop self-healing electrodes and bio-transistors for prolonged bioelectronic applications. Read more: Advanced Materials.

2. Tissue-like organic bioelectronics (materials, physics, fabrication)

Organic electrochemical transistor (OECT) is a flagship technology among organic bioelectronic devices. It is considered as the perfect link between biology and microelectronics considering the property similarities at large. However, the mechanical mismatch at the biotic-abiotic interface causes stability issues. Here, we develop tissue-like stretchable and healable OECTs to facilitate their interfacing with soft tissues by materials development and device engineering. Read more: Chemistry of Materials, Advanced Science, Advanced Electronic Materisals, Advanced Functional Materials, Journal of Materials Chemistry C.

3. Fully-integrated wearable system: sense, compute, control

Multi-modal biowearable systems: Despite the significant potential of organic/hydrogel bioelectronics for conformable human-centric healthcare applications, the absence of a compact readout platform impairs wearability of the entire system. We developed the PERfECT readout platform—a coin-sized, low-power, and multiplexed unit designed for wearable analysis of organic/hydrogel electrodes and biotransistors. Here, we develop multi-modal biowearable systems capable of revealing health parameters that cannot be discerned with a single parameter alone. Simultaneously, we develop closed-loop biowearables for sensor-controlled automatic medicine, such as glucose sensing and insulin injection. Read more: Analytical Chemistry, Nature, IEEE Electron Device Lett., AllAboutCircuits, Animation of sensing.

Funded by:
▪️ Innovation and Technology Commission (ITC), Mainland-Hong Kong Joint Funding Scheme (National Key R&D Program, 國家重點研發計劃).
▪️ Shenzhen Science and Technology Innovation Committee (SZSTI) Shenzhen-Hong Kong-Macau Science and Technology Program (Type C).
▪️ University Grants Committee Theme-based Research Scheme.