Neural Interfaces

-. Neural Interfaces for CNS

: Neural interfaces for CNS is divided to DBS (Deep Brain Stimulation) and spinal cord regeneration.

• DBS neural interfaces

: We have developed DBS neural interfaces based on Si and polymer substrate for flexibility. Each device is developed for electrical stimulation, optical stimulation (Optogenetics), or magnetic stimulation. All DBS neural interfaces are developed with multi-functionalities, such as electrical and optical stimulation, neural signal recording, and drug delivery. Additionally, DBS neural interface for magnetic stimulation is developed with both invasive and non-invasive types in mind. All designs of magnetic stimulation is developed with simulation results verifying feasibility of various coils and layer combinations.

• Neural interfaces for Spinal Cord Regeneration

: The Spinal Cord neural interfaces are developed with the integration of highly porous polymer scaffold and sieve neural devices for inducing Spinal Cord Regeneration and neural signal monitoring after injury. We have developed various types of neural interfaces, and we optimized surgical methods for the implantation of neural interfaces into to Rats for preclinical studies.

-. Neural Interfaces for PNS

: The existing robotic prosthetic arms are controlled via electromyography (EMG) signals, and are only capable of simple movements. Additionally, the amputee is not given any sensory feedback via the prosthetic arm.

: The ultimate goal of the current research project is to develop a prosthetic arm capable of executing precise and complex movements controlled by motor neural signals obtained from the peripheral nerve, and to give sensory feedback, obtained from the various physical sensors of the prosthetic arm, by generating sensory neural signals and stimulating the peripheral nerves. More specifically, our lab is involved in research and development of the electrodes for peripheral nerve interface that is capable of bidirectional neural signal communication with the peripheral nerve.

: Various neural electrodes have been developed over the years. However, there have not been a successful report of a device that is capable of long-term implantation, and most designs require heavy trade-off between the neural selectivity and invasiveness of the device. Therefore, our research team is developing a bidirectional novel neural electrodes for the peripheral nerve based on MEMS fabrication technologies.

: Due to recent increase in neuroprosthetic research fields, PNS neural interfaces for bidirectional motor and sensory transmission have became a focus. Thus, we focused on PNS neural interface development with prior experience in CNS neural interfaces. Our PNS neural interfaces include Sieve type, and Spiral type neural interfaces. The feasibility of every neural interface is verified through in-vivo experiments.

: Development of neural electrodes for the peripheral nerve

1. Design and MEMS fabrication of Peripheral Nerve Interface (PNI) integrated with multi-channel (32+) electrodes for neural signal acquisition and neural stimulation
2. Realization of structural and material optimization for long-term implantable neural electrode via the continuous evaluation of the peripheral nerve interface
3. Electrochemical (impedance) analysis and evaluation of the fabricated peripheral nerve electrodes
4. Quantitative evaluation of the motor and sensory signal obtained from the implanted peripheral nerve electrodes
5. Evaluation of the maximum days of neural signal acquisition, neural stimulation, and implantation via implanted peripheral nerve electrodes

: Therefore in order to optimize the high spatial resolution and minimize invasiveness of the developed peripheral nerve interface, the placement of the neural electrode probes into the nerve at specific angle and positions is needed. In order to achieve this goal and minimize the surgical procedure duration, our lab is developing a peripheral nerve electrode insertion device in tandem with the development of the peripheral nerve interface.

: Development of Peripheral Nerve Electrode Insertion Device

1. Design and fabrication of the insertion device in tandem with the development of the peripheral nerve electrode
2. Further revision and improvement of the insertion device via the evaluation of implantation procedure
3. Evaluation of the insertion device via implantation of the peripheral nerve electrodes into the rat sciatic nerve and primate peripheral nerve