Silk Fibroin, Sericin, and Conductive Silk Composites for Skin-Attachable Transient Electronics

The recent advancement in transient electronics has proposed environmentally responsible technologies and bioresorbable devices in response to the growing concern about electronic waste (e-waste) and the demand for physiologically friendly epidermal electronics, respectively. The selection of materials in the development of such electronics is crucial to achieving key properties, including biodegradability, biocompatibility, and flexibility. This study is designed to discover and demonstrate the suitability of silk proteins, specifically fibroin and sericin, as building blocks for biocompatible transient electronics that can be attached to the skin. The characteristics of silk proteins are optimized for the study by controlling the annealing temperature of the fibroin film for its robustness under aqueous conditions and adding ion additives to sericin for improved adhesion strength. Incorporating tungsten microparticles into a fibroin solution yields conductive silk composites that function as both electrodes and sensing materials. The composites are integrated with fibroin films and sericin adhesive, forming silk-based sensors with the capability to detect mechanical strain, capacitive touch motions, and electrophysiological signals, such as electroencephalography. The results illustrate the versatile use of silk materials for biodegradable sensors with reliable sensing abilities, which also contribute to the minimization of toxic electronic waste as part of sustainable technology.