Professor Hyunjoo Lee and her research team members developed the epidermal electric device which robustly adheres to the human skins by using the silk polymer.
The silk fibroin, thanks to its high biocompatibility and biodegradability, has been widely explored as biocompatible polymer substrates, and water-soluble sacrificial layers for biomedical. Professor Lee’s team focused on the adhesive properties of silk fibroin, which is modified by calcium(Ca) ion. They used the Ca-modified silk to overcome the limits of the conventional silk fibroin and developed the biocompatible and strong adhesive.
The metal–chelate bonding and water-capturing of Ca ions enhanced the viscoelasticity and thus the mechanical interlocking of the silk ﬁlm. This enhanced mechanical interlocking at the interface with the biological surfaces and resulted in the adhesive characteristics. Moreover, the ionic conductivity which is induced by Ca ions allows silk fibroin to remove the adhesion in the certain condition.
Professor Lee’s team developed the flexible capacitive touch sensor which can be easily attached and detached from the human skins by using the developed silk fibroin adhesive. They also fabricated a resistive strain sensor which has a strong adhesion and observed the resistance changes according to change in bladder tissue.
Professor Lee said, “This research shows the new possibilities of the silk fibroin by developing the biodegradable and reusable strong adhesive by using biocompatible silk polymer “It can be applied to epidermal and internal implantable electronic devices in the bioengineering field.” The developed silk conductive adhesive film is expected to be applicable to patients, who require the long-term monitoring and drug administration.
This research, which Dr. Jiwon Seo, Ph.D. candidate Hyojung Kim, Dr. Kyuhan Kim, Professor Siyoung Choi, and Professor Hyunjoo Lee participated, was published in the cover paper of “Advanced Functional Materials” on September 5. This work was funded by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), the Ministry of Health & Welfare, Republic of Korea.
Paper: Calcium-modified silk as a biocompatible and strong adhesive for epidermal electronics
The cover of “Advanced Functional Materials”