Abstract

Biomedical prosthetics utilizing electrical stimulation have limited, effective spatial resolution due to spread of electrical currents to surrounding tissue, causing nonselective stimulation. So, precise spatial resolution is not possible for traditional neural prosthetic devices, such as cochlear implants. More recently, alternative methods utilize optical stimulation, mainly infrared, sometimes paired with nanotechnology for stimulating action potentials. Infrared stimulation has its own drawbacks, as it may cause collateral heating of surrounding tissue. In previous work, we employed a plasmonic method for stimulation of an electrically excitable neuroblastoma cell line, which had limited success. Here, we report the development of a hybrid electro-plasmonic stimulation platform for spatially and temporally precise neural excitation to address the above deficiencies. Primary trigeminal neurons were costimulated in vitro in a whole-cell patch-clamp configuration with subthreshold-level short-duration (1-5 ms) electrical and visible light pulses (1-5 ms). The visible light pulses were aimed at a gold-nanoparticle-coated nanoelectrode placed alongside the neuron, within 2 μm distance. Membrane action potentials were recorded with a 3-fold higher success rate and 5-fold better poststimulation cell recovery rate than with pure optical stimulation alone. Also, electrical stimulus current input was being reduced by up to 40%. The subthreshold levels of electrical stimuli in conjunction with visible light (532 nm) reliably triggered trains of action potentials. This single-cell hybrid activation was reliable and repeatable, without any damage as observed with pure optical stimulation. This work represents an empirical cellular study of the membrane action potential response produced by the cultured primary sensory trigeminal neurons when costimulated with plasmonic and electrical (hybrid) stimulation. Our hybrid neurostimulation method can be used toward development of high-acuity neural modulation prosthetic devices, tunable for individual needs, which would qualify as a preferred alternative over traditional electrical stimulation technologies.

Department(s)

Chemical and Biochemical Engineering

Comments

National Institutes of Health, Grant P01AG009524

Keywords and Phrases

cochlear implants; electro-plasmonic hybrid stimulation; gold nanoparticles; localized surface plasmon resonance; neuromodulation; trigeminal neurons; visible light

International Standard Serial Number (ISSN)

1936-086X; 1936-0851

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 American Chemical Society, All rights reserved.

Publication Date

22 Sep 2020

PubMed ID

32603090

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