Multicolor Neural Optoelectrode Thermal Isolation
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Solution Overview
Problem
Current optogenetic tools face challenges in delivering low-cost, practical solutions for precise neural circuit manipulation with high spatial and temporal resolution, as existing optoelectrodes require excessive power and can cause thermal damage due to device heating, and lack efficient optical coupling schemes.
Innovation Solution
The development of a fiberless, multicolor optoelectrode with a monolithically integrated gradient index (GRIN) lens for efficient end-fire coupling between side-emitting injection laser diodes and a dielectric waveguide, which provides thermal isolation and improved alignment tolerance, enabling precise neural stimulation and recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light sources are placed on the surface of brain or large fibers are placed in the brain parenchyma, then optical stimulation can be delivered to deep brain structures, but excessive power is required which causes thermal damage to surrounding tissue
Solution Approach 1:
The patent extracts the light source from the traditional configuration (surface placement or large fiber placement) and repositions it to the back-end of the probe, connected through optical fibers. This separation allows the light source to be positioned away from the brain tissue, delivering optical stimulation to deep structures without requiring excessive power at the tissue interface, thereby avoiding thermal damage.
Solution Approach 2:
Optical fibers serve as intermediaries to transmit light from the back-end light source to the optical emission ports on the probe shanks. This intermediary transmission system enables efficient light delivery to deep brain structures without requiring the light source to be in direct contact with or near the tissue, thus preventing thermal damage while maintaining effective optical stimulation.
2Ease of manufacture
If manual attachment of fibers glued to portable light sources is used, then optoelectrodes can be assembled, but the process is highly variable and labor-intensive
Solution Approach 1:
The patent merges the light source, optical coupling elements (GRIN lenses), and waveguides into a monolithically integrated assembly at the back-end of the probe. This integration eliminates the need for manual fiber attachment and gluing procedures, providing a standardized, reproducible manufacturing process that is not labor-intensive while maintaining precise optical alignment.
Solution Approach 2:
The patent replaces the mechanical assembly process (manual fiber attachment and gluing) with a monolithic integration approach where optical components are precisely positioned and integrated during probe fabrication. This substitution eliminates variability and labor-intensive steps while ensuring consistent optical coupling efficiency.
3Illumination intensity
If optical fibers are used to transmit light from the probe back-end to the optical emission port, then light delivery is achieved, but device heating occurs which can cause thermal damage
Solution Approach 1:
Optical fibers act as intermediaries that efficiently transmit light from the back-end source to the emission ports with minimal heat generation. The fiber optic transmission medium converts electrical-to-optical energy conversion to occur at the cool back-end, transmitting only photons through the fiber to the probe tip, thereby avoiding heating at the tissue interface while maintaining effective light delivery.
Solution Approach 2:
The patent extracts the heat-generating light source conversion process from the probe tip location and relocates it to the back-end of the device. By taking out the electrical-to-optical conversion from the vicinity of the brain tissue, the system avoids thermal damage while maintaining effective optical stimulation through efficient fiber optic transmission.
4Loss of energy
If efficient optical coupling between light source and waveguide is achieved, then optical transmission is optimized, but the coupling scheme must be precisely aligned which increases manufacturing complexity
Solution Approach 1:
The patent replaces complex mechanical alignment procedures with a monolithic integration approach where GRIN lenses and waveguides are precisely positioned relative to each other during probe fabrication. This integration substitutes manual alignment with a standardized manufacturing process that ensures optimal optical coupling without requiring complex alignment procedures.
Solution Approach 2:
The patent merges the light source, GRIN lenses, and waveguides into a single integrated back-end assembly. This merging of optical components eliminates the need for separate alignment procedures, as all components are positioned relative to each other during monolithic fabrication, achieving efficient optical coupling while simplifying the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for independent activation and silencing of neural circuits with reduced heat conduction to the probe tip, prolonging operational time and minimizing tissue heating, thereby enabling precise neural circuit manipulation with unmatched spatial precision and scalability.
Implementation Method 1
a lens optically coupled between the light source and the light guide such that light from the light source can be directed by the lens to the light guide
Implementation Method 2
monolithically integrated gradient index (GRIN) lens for efficient end-fire coupling between side-emitting injection laser diodes and a dielectric waveguide, which provides thermal isolation
Data Source
AI summary
An optoelectrode having a lens optically coupled between a light source and a light guide and a method of making an optoelectrode. In one embodiment of the optoelectrode, the lens is a gradient index (GRIN) lens and the light source is a side-emitting injection laser diode (ILD). The optoelectrodes can be implemented such that they are high density, highly compact, monolithically integrated, and can deliver multicolor light output independently and simultaneously at a common waveguide port using an optical mixer, for example. In a preferred embodiment, the optoelectrodes are used as neural probes.