Liquid crystal electro-optical transducers for electrophysiology sensing applications

Area of Science:

• Biomedical Engineering
• Optoelectronics
• Neuroscience

Background:

• Electrophysiology traditionally uses electronic electrodes and wires for bioelectric signal sensing and transmission.
• Current electronic methods face limitations in bandwidth, signal conditioning, and channel count, especially for invasive or miniature devices.

Purpose of the Study:

• To demonstrate an alternative approach for sensing and transmitting electrophysiological signals using light instead of electronics.
• To develop a microscale, passive, fluorophore-free optrode based on liquid crystal birefringence.

Main Methods:

• Development of a microscale optrode utilizing the birefringence property of liquid crystals.
• Testing the optrode's linearity, relative responsivity, and bandwidth for electrophysiology signal transduction.
• Fabrication of multi-optrode arrays to demonstrate miniaturization potential.

Main Results:

• Optrodes exhibited high linearity (99.4 ± 0.5%), suitable relative responsivity (57 ± 12%V⁻¹), and a bandwidth of 11.1 ± 0.7 kHz.
• Successfully captured rabbit cardiac sinoatrial electrograms and sciatic nerve action potentials.
• Demonstrated fabrication of multi-optrode arrays with automated interface matching.

Conclusions:

• Liquid crystal optrodes offer a viable method for converting bioelectric signals to the optical domain.
• This technology can enable high-bandwidth optical interfaces for ultra-miniature neural and cardiac applications.
• The approach paves the way for integrating optical telecommunications in clinical diagnostics and research.