Mesoscopic‐Functionalization of Silk Fibroin with Gold Nanoclusters Mediated by Keratin and Bioinspired Silk Synapse

Abstract

Silk fibroin (SF) offers great opportunities in manufacturing biocompatible/partially biodegradable devices with environmental benignity and biomedical applications. To obtain active SF devices of next generation, this work is to demonstrate a new functionalization strategy of the mesoscopic functionalization for soft materials. Unlike the atomic functionalization of solid materials, the meso-functionalization is to incorporate meso-dopants, i.e., functional molecules or nanomaterials, quantum dots, into the mesoscopic networks of soft materials. In this work, wool keratin (WK) molecules were adopted as mediating molecules to incorporate gold nanoclusters (AuNCs), into the mesoscopic networks of SF. It follows from our analyses that the β-crystallites between WK and SF molecules establish the binding between WK@AuNCs and the SF networks. The incorporated WK@AuNCs are electron rich and serve as electronically charged nano particles to bridge the growth of Ag filaments in bio-degradable WK@AuNCs-SF memristors. The meso-functionalization can greatly enhance the performance of SF materials and endows them with new functionalities. This can be highlighted by biocompatible/partly degradable WK@AuNCs functionalized SF resistive random-access memories, having the enhanced resistive switching memory performance, and the unique synapse characteristics and the capability of synapse learning compared with neat SF devices, and of great importance in nonvolatile memory, analog circuits, and neuromorphic applications.

Self‐Assembled Networked PbS Distribution Quantum Dots for Resistive Switching and Artificial Synapse Performance Boost of Memristors

“…In other words, the HRS fitting results indicate that the charge‐transport behavior during the set process is in good agreement with the classical SCLC mode . In the LRS region of the orange frame, the fitted slopes are close to 1 (Figure S9c, Supporting Information), indicating ohmic conduction behavior and suggesting the formation of CFs during the set process . SCLC and the ohmic contact are responsible for the HRS and LRS, respectively, similar to other MDs operating by the Ag CFs RS mechanism …”

Memristive Synapses for Brain‐Inspired Computing

“…The difference is that the semiconducting or insulating switching layer does not contain movable metal ions or metal clusters; movable metal ions come from the redox reaction at the active electrode/switching layer interface upon electrical bias. The active electrode material is always Cu or Ag, and the switching layer can be Ta 2 O 5 , ZnO, HfO 2 , WO 3− x , ZnS, GeSe, SiGe, amorphous silicon, amorphous carbon, polymer, and silk fibroin . It has been found that lightly oxidized ZnS films present highly controllable memristive switching and synaptic performance, originating from a two‐layer structure of ZnS thin films, i.e., the lightly oxidized layer and unoxidized layer .…”

Vacancy‐Induced Synaptic Behavior in 2D WS2 Nanosheet–Based Memristor for Low‐Power Neuromorphic Computing

“…Fitting results for the HRS (Figure S9c, Supporting Information) of the Ag/WS 2 /Pt device show that the charge transport behavior agrees well with the classical trap‐controlled space charge limited conduction, which is comprised of three sections. In the low‐voltage region from 0 to 0.6 V, the slope of 1.10 (close to 1) indicates the Ohmic region ( I ∝ V ); the voltage then increases from 0.6 to 1.7 V in the Child's law region ( I ∝ V 2 ) with the slope being 1.75; finally, there is a steep current increase region (1.7–3.4 V) with a slope of 3.28 . Furthermore, the I – V characteristics in the LRS of Ag/WS 2 /Pt are fitted as shown in Figure S9d (Supporting Information), where an Ohmic conduction behavior with a slope of ≈1 is apparent.…”