Humidity-Induced Protein-Based Artificial Synaptic Devices for Neuroprosthetic Applications

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Neuroprosthetics and brain-machine interfaces offer significant benefits for individuals with neurological disabilities.
• Future neural repair systems require energy-efficient, real-time neuromorphic devices.
• Conventional synaptic devices are incompatible with the high-humidity environment of the central nervous system's cerebrospinal fluid (CSF).

Purpose of the Study:

• To develop artificial synaptic devices compatible with high-humidity environments for neuromorphic applications.
• To create biocompatible devices that mimic biological nerve function for in-body applications.
• To enhance the functional stability of artificial synapses in humid conditions.

Main Methods:

• Fabrication of artificial synaptic devices using a gelatin-PEDOT: PSS composite as the active material.
• Testing device performance in a high-humidity environment (approximately 90% relative humidity).
• Evaluation of various synaptic properties, including excitatory/inhibitory post-synaptic current (EPSC/IPSC) and plasticity mechanisms.

Main Results:

• The gelatin-PEDOT: PSS composite devices demonstrated effective functionality in a high-humidity environment (≈90% RH).
• Devices successfully mimicked key synaptic properties such as EPSC/IPSC, paired-pulse facilitation/depression (PPF/PPD), and spike-rate dependent plasticity (SRDP).
• Demonstrated spike-voltage dependent plasticity (SVDP) and spike-duration dependent plasticity (SDDP) at high humidity levels.

Conclusions:

• The developed artificial synaptic devices are suitable for high-humidity environments, addressing a key limitation for in-body neuromorphic applications.
• The gelatin-PEDOT: PSS composite shows promise for creating stable, biocompatible artificial synapses.
• These findings pave the way for advanced neural repair systems and brain-machine interfaces.