Flexible Polymer Electrodes for Stable Prosthetic Visual Perception in Mice.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Materials Science

Background:

• Future neuroprosthetics require brain interfaces capable of long-term, low-damage neuronal stimulation.
• Flexible, thin polyimide shanks with microelectrodes are a potential solution.

Purpose of the Study:

• To evaluate the long-term performance and biocompatibility of thin polyimide microelectrode arrays for neural stimulation.

Main Methods:

• Fabrication of thin polyimide shanks with small (<15 µm) electrodes.
• In vitro testing of electrode stability under high electrical pulse counts.
• In vivo implantation in the mouse primary visual cortex (V1) for microstimulation studies.
• Assessment of perceptual thresholds and long-term device functionality and tissue response.

Main Results:

• Electrodes demonstrated remarkable stability with billions of electrical pulses in vitro.
• In vivo perceptual thresholds for microstimulation were low (2-20 µA), well below device limits.
• Devices maintained stable performance for over a year in vivo with minimal brain tissue damage.

Conclusions:

• Thin, flexible polyimide microelectrodes exhibit excellent long-term stability and biocompatibility.
• These findings support the potential of these electrodes for developing advanced neuroprosthetics.
• The technology shows promise for the long-term restoration of lost sensory functions.