Neuromodulation using electroosmosis.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Ophthalmology

Background:

• Photoreceptor (PR) degenerative diseases cause vision loss.
• Chemical stimulation of retinal neurons using glutamate is a potential treatment strategy.
• Previous pneumatic actuation methods are difficult to miniaturize for implants.

Purpose of the Study:

• Evaluate electroosmotic flow (EOF) for delivering glutamate to the retina.
• Assess EOF's potential for miniaturization in an implantable device.

Main Methods:

• Constructed an EOF microfluidic device for dispensing glutamate.
• Tested the device's ability to stimulate retinal output in an in-vitro rat retina model.
• Utilized 3D printed and off-the-shelf components for the EOF system.

Main Results:

• The EOF device delivered small, pulsatile volumes of glutamate with low voltage.
• Excitatory and inhibitory spike rate responses were observed in PR-degenerate rat retina.
• Glutamate-evoked responses were voltage-dependent and localized.

Conclusions:

• EOF is a viable mechanism for chemical retinal stimulation, comparable to pneumatic injectors.
• The EOF device eliminates miniaturization challenges associated with pneumatic systems.
• EOF-driven chemical stimulation is a promising approach for retinal prosthetics.