A Biodegradable and Stretchable Protein-Based Sensor as Artificial Electronic Skin for Human Motion Detection

Due to the natural biodegradability and biocompatibility, silk fibroin (SF) is one of the ideal platforms for on-skin and implantable electronic devices. However, the development of SF-based electronics is still at a preliminary stage due to the SF film intrinsic brittleness as well as the solubility in water, which prevent the fabrication of SF-based electronics through traditional techniques. In this article, a flexible and stretchable silver nanofibers (Ag NFs)/SF based electrode is synthesized through water-free procedures, which demonstrates outstanding performance, i.e., low sheet resistance (10.5 Omega sq(-1) ), high transmittance (>90%), excellent stability even after bending cycles >2200 times, and good extensibility (>60% stretching). In addition, on the basis of such advanced (Ag NFs)/SF electrode, a flexible and tactile sensor is further fabricated, which can simultaneously detect pressure and strain signals with a large monitoring window (35 Pa-700 kPa). Besides, this sensor is air-permeable and inflammation-free, so that it can be directly laminated onto human skins for long-term health monitoring. Considering the biodegradable and skin-comfortable features, this sensor may become promising to find potential applications in on-skin or implantable health-monitoring devices.