An investigation of high refractive index silicone as a light guiding material for optogenetic applications

There is currently a lack of waveguides that are compliant and elastic enough to be suitable for a variety of implantation applications. High refractive index silicones have the mechanical and optical properties that might make them useful as an implantable waveguide. A high refractive index silicone from the optical encapsulant category of silicones (Gelest OE50) was fabricated into simple waveguides and its potential as an implantable waveguide was investigated. It was found that while the elasticity and stiffness of the Gelest OE50 was not affected by exposure to an environment simulating that of the body, the optical clarity was. The attenuation coefficent was found to increase from 0.1165 dB/mm to 0.2081 dB/mm, a increase significant enough to make it difficult to recommend for use as a material for implantable waveguides.