Meso‐Reconstruction of Silk Fibroin based on Molecular and Nano‐Templates for Electronic Skin in Medical Applications

Abstract

A unique strategy of mesoscopic functionalization starting from silk fibroin (SF) materials to the fabrication of meso flexible SF electronic skin (e-skin) is presented. Notably, SF materials of novel and enhanced properties of the materials can be achieved by mesoscopically reconstructing the hierarchical structures of SF materials, based on rerouting the refolding process of SF molecules by meso-nucleation templating. Mesoscopic hybridization/reconstruction endows cocoon silk with a robust mechanical and electric performance by incorporating wool keratin (WK) and carbon nanotubes (CNTs) into the mesostructures of SF via intermolecular templated nucleation. Furthermore, the asymmetrical meso-functional films with biocompatibility and insulation on one side and conductivity on the other (square resistance = 130 Ω sq −1 ) endow the passive wireless e-skin exhibited a tunable sensitivity from −1.05 to −6.35 kPa −1 with a lossless measurement range of ≈2 kPa. The pulses of human subjects are monitored using the e-skin to evaluate blood vessel hardening and real-time dynamic systolic and diastolic blood pressure.

From Mesoscopic Functionalization of Silk Fibroin to Smart Fiber Devices for Textile Electronics and Photonics

“…[35] Meso-hybridization is the rebuilding of mesoscopic networks of SF nanofibril networks by incorporating macromolecules into meso-hierarchical networks of SF materials via heteromolecular nucleation templating. [3] This enables partial structures of macromolecules, e.g., WK, to be incorporated into the meso-hierarchical networks of SF materials. [3] In the case of meso-hybridization of SF by WK, molecular spring-like 𝛼-helices of WK molecules are built into the meso-hierarchical networks of SF materials.…”

“…This type of SF-WK meso-hybrid sensor can be utilized to monitor a variety of motion and physiological signals, such as vocal cord vibrations, pulse fluctuations, and joint movements and to promote sophisticated human-machine interactions for personalized healthcare, such as blood vessel elasticity evaluation and dynamic blood pressure prediction based on the pulse wave signals. [3] Carbonization is another technology that can convert insulating silk materials into electrically conductive and pressure/strain sensitive materials. [116][117] During carbonization, silk fabrics transformed N elements into N substituents in graphite or amorphous layers, [118] showing good electrical conductivity (≈140 Ω sq −1 ).…”

“…Fibrous or textile electronics and photonics are devices integrated in flexible yarns or textiles that perform smart sensing or logic functions. [ 1 , 2 ] This special type of electronic or photonic elements significantly impact smart clothes, [ 3 ] which are applicable for movable energy harvesting, [ 4 , 5 , 6 , 7 , 8 ] remote diagnosis, [ 3 , 9 ] personalized medical healthcare, [ 10 , 11 , 12 , 13 ] long‐time motion tracking, human–machine interaction, [ 14 , 15 , 16 ] and wearable display. [ 17 ] Silk fibers from silkworms are one of the most important natural fibers for applications in smart and wearable electronics ( Figure 1 ).…”

“…e) CNT/SF hybrid mesoscopic networks characterized by AFM image. Reproduced with permission [3]. Copyright 2021, Wiley-VCH.…”

“…e,f) AFM images of SF nanofibrils and SF/WK hybrid nanofibrils, and schematic illustration of the claw structure. a-f) Reproduced with permission [3]. Copyright 2021, Wiley-VCH.…”