Fiber Optrode with Microstructured Tips for Precise Light Delivery in Optogenetic

Abstract:
Optogenetic modulation needs precise light delivery to deep brain areas. Traditional flat cleaved optical fibers, often combined with electrodes, cause tissue damage and limit spatial illumination control. Tapered fibers, however, offer better tissue compatibility and illumination control. Our study introduces a method for fabricating tapered fiber tips via grinding, which enhances targeted neural photo-stimulation. We explored various cone angles (14deg, 30deg, 60deg, 90deg) for their impact on illumination and optical throughput. A custom grinding setup produced high-quality microscopic cone tips, and optical testing revealed that transmitted power decreases with smaller cone angles. Fluorescence emission profiles showed significant variation in illumination due to cone angles. Electrochemical impedance spectroscopy highlighted how electrode size affects recording capability. Overall, tapered fiber-based optrodes provide controlled, less invasive light delivery and allow neuroscientists to optimize stimulation based on their specific requirements.