Scientists from the University of Cologne led by Priv. Doz. Dr. Hajar Maleki in Germany, in collaboration with the Technical University of Denmark (DTU), developed biomimetic flexible electronic materials with self-healing properties. Their research combines silk fibroin and MXene nanosheets to create innovative soft materials suitable for soft electronics and wearable sensors applications.
The materials are described in a new paper in ACS Applied Nano Chemistry.
MXene is a special type of 2D material that consists of thin layers of metal carbides or nitrides. These layers are incredibly thin, just a few atoms thick. MXene materials are known for their excellent electrical conductivity and mechanical strength. Because of their unique properties, they can be used in various electronic applications, such as flexible circuits and sensors. Silk fibroin, on the other hand, is a natural protein that is extracted from silkworm cocoons, and it is known for its strength, durability, biocompatibility and degradability.
In the context of the article, researchers have combined MXene with silk fibroin using a special chemical process inspired by the adhesiveness properties of mussels to the surfaces. By combining these two materials, they have created flexible electronic materials that have the strength and electrical conductivity of MXene and the biocompatibility of silk fibroin. These materials can be used to make electronic devices that can bend and stretch without breaking, making them suitable for wearable devices and other applications where flexibility is important. Additionally, the self-healing properties of these materials mean that they can repair themselves when damaged, increasing their durability and lifespan. As the world moves towards the Internet of Things and artificial intelligence, there is a growing need for such electronic devices that are flexible and can repair themselves, since traditional electronics made of silicon are rigid and less suitable for wearable applications.
The synthesis process of gums, hydrogels, and aerogels involved the coordination of oxidized silk fibroin (SF-DOPA), tannic acid, polydopamine-modified MXene nanosheets, and ferric ions. By controlling the molar ratio and pH values, the researchers could tailor the properties of the resulting materials, including elasticity and electrical conductivity. The optimized materials demonstrated high flexibility, with the gum-like materials stretching up to 600% of their original size. Additionally, their electrical conductivity reached a noteworthy value of 6.5 x 10-4 S cm-1.
The team showcased the potential of these materials by incorporating them into piezoresistive wearable pressure sensors, which exhibited excellent sensitivity and responsiveness to human motion, accurately detecting finger, knee, shoulder, and elbow movements. The self-healing properties of the materials ensure durability, making them suitable for long-term use and diverse applications.
The developed materials hold promises for personalized healthcare systems, mobile devices, human-machine interfaces, soft robotics, and in the field of personalized healthcare systems, where the flexibility and self-healing properties of these materials make them suitable for wearable health monitoring devices. Integrating sensors made from these biomimetic materials into garments or accessories allows individuals to continuously monitor their vital signs and movement, providing real-time data to healthcare professionals for early detection and intervention. Real-time data collection from individuals or the environment could also enhance efficiency, safety, and convenience in smart homes, transportation, and industrial monitoring.
In summary, developing biomimetic flexible electronic materials inspired by mussels represents a significant advancement in soft electronics. Combining flexibility, self-healing, and biodegradability open up new possibilities for adaptable, comfortable, and environmentally sustainable next-generation devices. With ongoing research and advancements in materials science, we can expect to see even more exciting applications in the near future.
Paolieri, M., Chen, Z., Babu Kadumudi, F., Alehosseini, M., Zorrón, M., Dolatshahi-Pirouz, A., & Maleki*, H. (2023). Biomimetic Flexible Electronic Materials from Silk Fibroin-MXene Composites Developed via Mussel-Inspired Chemistry as Wearable Pressure Sensors. ACS Applied Nano Materials, 6(7), 5211–5223. doi: 10.1021/acsanm.2c05140
University of Cologne