Transient bioelectrical devices inspired by a silkworm moth breaking out of its cocoon

Abstract

Transient devices have attracted extensive interest because they allow changes in physical form and device function under the control of external stimuli or related commands and have very broad application prospects for information security, biomedical care and the environment. Transient bioelectrical devices were fabricated inspired by a silkworm moth breaking out of its cocoon, which has shown many advantages, including the use of mild stimulation, biocompatible materials, a simple process, and a universal strategy. For the fabrication of the transient devices, heat-sensitive microspheres with a 9.3 mol L⁻¹ LiBr solution in wax shells were prepared by microfluidic technology, which were then assembled into silk fibroin (SF) electronic materials/devices, such as SF conductive film, an LED circuit on SF film, and a Ag/SF film/Pt/SF film memristor. The contribution from the LiBr/wax microspheres to the transient time of the SF films upon exposure to heat was quantitatively investigated. This approach was applied to transiently dissolve a flexible Ag-nanowire resistance circuit line on a SF substrate. Moreover, memristors constructed with a functional layer of SF were destroyed by melting the LiBr/wax microspheres. This technique paves the way for realizing transient bioelectrical devices inspired by biological behavior, which have been well optimized by nature via evolution.