New Material: New Progress In Research Based On Silk Protein

Recently, Tao Hu's team, a researcher at the Shanghai Institute of Microsystems and Information Technology, Chinese Academy of Sciences, made progress in the research of highly adaptive silk protein neural interface. The team cooperated with the Sixth People's Hospital affiliated to Shanghai Jiaotong University School of Medicine to develop an implantable bioelectronic device with high tissue/organ adaptability based on silk protein materials. On the basis of retaining the good biocompatibility of silk protein materials, the water triggered controllable geometric reconstruction of the device is realized by using the super shrinking properties of silk protein materials and the bonding process, which further realizes the matching of geometric structure and function between the device and target tissues or organs. The relevant research results are as follows: Adaptive Bioelectronic Silk based Implants, published in Advanced Materials on July 22 Materials).

Biocompatibility is one of the most important attributes of implantable bioelectronic devices, including but not limited to biocompatibility, mechanical matching, geometric matching and functional matching. Silk protein material is a good material for preparing biomedical implants and has been applied clinically. It has excellent properties such as no biological toxicity, no rejection reaction, biodegradability in vivo, flexibility, adjustable mechanical properties and functionalization. However, biopolymers, such as silk protein, still face certain risks and challenges when they are used to prepare bioelectronic devices: currently, flexible electronic devices are often attached to target tissues or organs by passive deformation, and the attachment effect is limited; Due to the dissolution characteristics of these materials, the functional structures prepared on their surfaces may tear with the expansion of their surface areas, so they cannot work in vivo for a long time.

In response to the above challenges, researchers based on the super shrinkage characteristics of silk protein film to ensure that the functional structure of the protein film surface does not break when exposed to water, combined with the bonding process and structural design of multi-layer silk protein film, developed a deformation controllable water triggered geometric reconstruction protein film, and realized specific functions through the MEMS process and functional protein film.

Inspired by climbing plants, the research team further developed a spiral electrode for peripheral nerves based on the double-layer crimpable silk protein film and MEMS process, and verified its electrophysiological stimulation, recording function and medium and long-term in vivo biocompatibility in rats. The experiment shows that the electrode can be geometrically reconstructed by water triggering, so that it can be closely attached to the peripheral nerve of rats and form a good bio electronic interface. After long-term in vivo implantation, no significant rejection reaction caused by electrodes occurred. The above results indicate that multi-layer geometrically reconfigurable protein films have good application prospects in the preparation of highly adaptive bioelectronic devices.

The research was supported by the National Key R&D Program of the Ministry of Science and Technology, the National Natural Science Foundation of China, the "0 to 1" original innovation project of the Basic Frontier Scientific Research Program of the Chinese Academy of Sciences, the Shanghai Municipal Major Special Project, and the Special Basic Research Zone Program of the Shanghai Branch of the Chinese Academy of Sciences.

Based on the super shrinking property of silk protein and the bonding process, a water triggered geometric reconfigurable protein film was developed.