Silk-Based Advanced Materials for Soft Electronics

Abstract

Conspectus Soft bioelectronics that could be integrated with soft and curvilinear biological tissues/organs have attracted multidisciplinary research interest from material scientists, electronic engineers, and biomedical scientists. Because of their potential human health-related applications, soft bioelectronics require stringent demands for biocompatible components. Silk, as a kind of well-known ancient natural biopolymer, shows unique combined merits such as good biocompatibility, programmable biodegradability, processability into various material formats, and large-scale sustainable production. Such unique merits have made silk popular for intensive design and study in soft bioelectronics over the past decade. Due to the development of fabrication techniques in material processing and progress in research, silk has been engineered into a variety of advanced materials including silk fibers/textiles, nanofibers, films, hydrogels, and aerogels. Natural and regenerated silk materials can also be transformed into intrinsically nitrogen-doped and electrically conductive carbon materials, due to their unique molecular structure and high nitrogen content. The rich morphologies and varied processing options for silk materials can furnish transformed carbon materials with well-designed structures and properties. The favorable and unique material merits of silk materials and silk-derived carbon materials offer potential applications in soft electronics. Based on commercial silk fibers/textiles and the availability of re-engineered silk materials with versatile technological formats, functional soft electronics have been explored with silk as flexible biosupports/biomatrixes or active components. These soft systems include bioresorbable electronics, ultraconformal bioelectronics, transient electronics, epidermal electronics, textile electronics, conformal biosensors, flexible transistors, and resistive switching memory devices. Silk-derived carbon materials with rationally designed morphologies and structures have also been developed as active components for wearable sensors, electronic skins, and flexible energy devices, which provide novel concepts and opportunities for soft electronics. In this Account, we highlight the unique hierarchical and chemical structure of natural silk fibers, the fabrication strategies for processing silk into materials with versatile morphologies and into electrically conductive carbon materials, as well as recent progress in the development of silk-based advanced materials (silk materials and silk-derived carbon materials) for soft bioelectronics. The design and functionality of soft electronics developed with commercial silk fibers/textiles, re-engineered silk materials, and silk-derived carbon materials as biosubstrate/matrix and active components is introduced in detail. We further discuss future challenges and prospects for developing silk-based soft bioelectronics for wearable healthcare systems. By leveraging the unique advantages of silk-based advanced materials, the design and con...

Stable and Biocompatible Carbon Nanotube Ink Mediated by Silk Protein for Printed Electronics

“…[41] Besides, fibroin, which is the other main protein in natural silk fibers, is also a well-known biomaterial for its good biocompatibility. [42,43] Compared with fibroin, sericin has smaller molecule Ink-based processes, which enable scalable fabrication of flexible devices based on nanomaterials, are one of the practical approaches for the production of wearable electronics. However, carbon nanotubes (CNTs), which possess great potential for flexible electronics, are facing challenges for use in inks due to their low dispersity in most solvents and suspicious cytotoxicity.…”

Flexible and Stretchable Microwave Electronics: Past, Present, and Future Perspective

“…It is noted that research exploring flexible/stretchable substrates suitable for microwave applications are ongoing. [113,166,277,278] Before any breakthrough happens, inventing a strategy to enhance the thermal conductivity of the present flexible substrates may be an alternative route to a suitable solution for this challenge. It is also noted that there have been no demonstrations of stretchable active microwave electronic circuits on any stretchable substrates.…”

Advances in Liquid Metal-Enabled Flexible and Wearable Sensors

“…With the rapid development of soft electronics [10][11][12][13][14][15][16][17][18][19][20], flexible and wearable sensors have shown evident advantages in biomedical applications, such as health-monitoring, wearable devices, artificial skin and intelligent robotics [10,[21][22][23][24][25][26][27][28][29][30][31]. For instance, strain sensors can be attached to human body and its melting point is 10.5 °C.…”