The State Key Laboratory of Sensing Technology, Shanghai Institute of Microsystems and Information Technology, Chinese Academy of Sciences, uses micro-nano processing technology to prepare a multi-channel ultra-flexible microelectrode array and integrates a multifunctional probe (Silk-Optrode) composed of natural silk protein fiber, which can realize the precise regulation and analysis
of brain nerve signals 。 On November 8, the research results were published in Microsystems & Nanoengineering under the title A silk-based self-adaptive flexible opto-electro neural probe
.
Analyzing neuroelectrical activity is the core of brain function analysis, and the combination of optogenetics and electrophysiological recordings enables high-precision two-way interaction between neural interfaces and neural circuits
.
The multifunctional neural probe can realize light stimulation and EEG signal recording at the same time, which is an important research direction
in the field of brain science and brain diseases.
Traditional photoelectrode probes are usually made of rigid silicon-based and metal, which is easy to cause inflammation of brain tissue; The flexible probe made of flexible polymer cannot be implanted into brain tissue by its own mechanical strength, requiring additional auxiliary means, which increases the difficulty of implantation surgery and easily leads to additional intraoperative injury
.
In view of the above dilemma, the scientific research team used micro-nano processing technology and biocompatible materials to develop a multifunctional probe Silk-Optrode, composed of natural silk protein optical fiber and multi-channel ultra-flexible microelectrode
array.
The photoprobe can be precisely implanted in the brain for simultaneous optogenetic stimulation and multichannel recording
of freely behaving animals.
Silk plays an important role
due to its high transparency, good biocompatibility and adjustable mechanical properties.
Through the hydration of the filament fiber, the probe can actively adapt to the environment after implantation in the brain tissue, reducing its own mechanical stiffness
.
After hydration, the bending stiffness of the probe is reduced to 2.
77E-10 N·m2, which is 4 orders of magnitude
lower than that of commercial fibers.
Thus, when implanted in the brain with high accuracy, the probe maintains mechanical compliance with surrounding brain tissue
.
In a space 200 μm diameter and 2 mm long, the photoprobe integrates 128 recording channels to record a single neural signaling unit
with high yield and good isolation while performing intracranial photostimulation with low optical loss.
Immunohistochemistry experiments two months after surgery showed that compared with rigid commercial probes, the probe produced less immune response and tissue damage at the implant-neural interface, and had good biocompatibility
.
This technology will provide new opportunities for the combination of multifunctional biomaterial invasive devices and neurological disease research, and has important application prospects
in the fields of brain function analysis and brain-computer interface.
The research work is supported
by the National Key Research and Development 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 Project, the "Basic Research Special Zone Program" of the Shanghai Branch of the Chinese Academy of Sciences, and the Shanghai Pujiang Talent Program.
Shanghai Microsystem Institute has developed an integrated multi-functional ultra-flexible microelectrode array
