Development of an Infrared Nerve Stimulator

Greg Wigger, Chris Tedder, and Melanie Gault

Advised by:Dr. Duco Jansen, Ph.D.

The Problem

This requires a reliable stimulation modality to gain better control over neural signals.

There is a need for an implantable device that will reliably stimulate individual nerve fascicles

Our Solution: Infrared Stimulation

Infrared StimulationSame advantages as electrical

stimulation, but: Less damaging to nerve Artifact free Spatially selective

Electrical StimulationHas fundamental shortcomings that

create a need for an alternative Contact can cause permanent damage

to nerve Stimulation artifact Hard to selectively stimulate

Rat Sciatic Nerve

Electrical Stimulator

-50510

0 2 4 6 8 10 12 14 16

CM

AP

(V)

Rat Sciatic Nerve

Electrical Stimulator

-5

05

10

0 2 4 6 8 10 12 14 16

CM

AP

(V)

Fiber Coupled Laser

Rat Sciatic Nerve-0.1

0

0.1

0.2

0 2 4 6 8 10 12 14 16

CM

AP

(V)

-0.1

0

0.1

0.2

0 2 4 6 8 10 12 14 16

CM

AP

(V)

Fiber Coupled Laser

Optical Fiber

Group ObjectiveDevelop an infrared nerve stimulator

containing optical fibers running parallel to the nerve fibers Create a single fiber prototype Create a four fiber prototype embedded in

a cuff to be wrapped around entire nerve bundle

Two models will be tested:

Fiber with angled mirror

Fiber polished at 45 degree angle

Past Work

Polished a fiber at 45 degrees Used varying sized grit paper and

worked our way down to 1 µm Observed beam profile of polished optic

fiber

Past Work (Continued)

Constructed of proof-of-concept prototype for mirror reflection

Current Work

Using the 3D design software, SolidWorks, to draw out the prototype This information will be used to

determine the necessary focal length in smaller scale models

Nylon Tubing Optical fiber with insert

Current Work (continued) Knife edge technique to characterize

beam width of side firing fiber Did this in a single direction

In contact with Ocean optics about optical fibers for high power infrared applications

Waiting for infrared transparent epoxy to come in so that we can construct our own.

Future Work

Receive larger nylon tubing and mirrors Current nylon tubing has inner diameter

of 0.32 inches (8.128 mm) The smallest standard concave mirror

diameter is 9 mm we need a larger tube!

Future Work (Continued)

Power output analysis for both side-firing techniques

Animal studies of both prototypes? Development of nerve cuff design

with 4 side-firing fibers Exploration of PDMS for biomaterial Customized building of best side-

firing fiber (custom ordered parts, smaller size, etc.)