Polydimethylsiloxane-based optical waveguides for tetherless powering of floating microstimulators

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Neural electrode implants often rely on percutaneous wires or transcutaneous power, susceptible to breakage and tethering forces.
• Spinal cord and brain stem electrodes face significant displacement, increasing the risk of device failure.
• Wireless powering solutions are needed to improve the reliability and longevity of neural implants.

Purpose of the Study:

• To investigate the feasibility of using polydimethylsiloxane (PDMS) optical waveguides for wireless power transmission to neural electrodes.
• To replace brittle metal wires with flexible, implantable optical waveguides.
• To assess the potential of optical waveguides for powering deep-tissue implanted devices.

Main Methods:

• Optically clear polydimethylsiloxane (PDMS) was utilized as a light waveguide.
• Light transmission and attenuation were measured through PDMS waveguides and human skin.
• PDMS waveguides were implanted in rats for a one-month in-vivo feasibility study.

Main Results:

• The attenuation of light along PDMS waveguides was measured at 0.36 ± 0.03 dB/cm.
• Transcutaneous light collection efficiency of cylindrical waveguides through human skin was determined to be 44% ± 11%.
• Successful one-month implantation of waveguides in rats demonstrated in-vivo optical transmission feasibility.

Conclusions:

• PDMS optical waveguides offer a viable method for wireless power delivery to neural implants.
• The characterized light attenuation and collection efficiency provide crucial data for designing future optical powering systems.
• This technology has the potential to enhance the reliability and reduce failure rates of implanted neural electrodes.