Flat Optogenetic Cuff Interface for Selective Nerve Stimulation
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Solution Overview
Problem
Current biomedical devices struggle to selectively stimulate and record specific axons in peripheral nerve fascicles without damaging the nerves, particularly due to power limitations and non-uniform stimulation effects in optogenetic approaches.
Innovation Solution
A flat optogenetic cuff interface (FOCI) that gradually reshapes a single fascicle to a height between 0.2 mm and 0.5 mm, reorganizing axons within the fascicle while using optically transparent materials and pulsed light sources to stimulate axons over the entire cross-section within safe power limits, enhancing specificity and addressing power constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional cuff electrode is used to stimulate peripheral nerves, then electrical stimulation can be applied to the nerve, but the stimulation lacks selectivity and activates all proximate nerves rather than specific axons
Solution Approach 1:
The cuff is divided into multiple discrete optical sources (LEDs or lasers) arranged in an array, each capable of independent activation. This segmentation allows selective stimulation of specific axon populations by activating only the necessary light sources, rather than stimulating all nerves proximate to the electrode as with traditional electrical stimulation.
Solution Approach 2:
Different regions of the cuff are equipped with optically transparent materials and optical sources that can be selectively activated to target specific local areas of the nerve. This enables localized stimulation of particular axons or fascicles while leaving other regions unaffected, providing spatial selectivity that electrical stimulation cannot achieve.
2Adaptability or versatility
If optogenetic stimulation is used to target specific axons, then selectivity is improved, but power limitations and non-uniform stimulation effects occur
Solution Approach 1:
The invention transitions from point-source or linear optical stimulation to a two-dimensional array of optical sources distributed across the cuff surface. This dimensional expansion allows light to be delivered from multiple angles and positions, achieving uniform illumination across the entire nerve cross-section and eliminating hot spots or under-stimulated regions.
Solution Approach 2:
Multiple optical sources are combined in an array configuration, with their individual light fields merging to create a uniform illumination pattern across the nerve. This collective action of multiple sources distributes the power load and ensures even stimulation across all targeted axons, overcoming the non-uniformity inherent in single-source approaches.
3Adaptability or versatility
If the nerve is flattened to increase selectivity, then specific axon populations become more addressable, but the individual axons may be damaged by the reshaping process
Solution Approach 1:
The cuff is pre-formed with an internal opening of the desired flattened geometry, and the nerve is gradually reshaped to match this pre-determined configuration. This preliminary preparation of the target geometry allows controlled, progressive deformation that reorganizes axons into a more addressable arrangement without exceeding the mechanical tolerance of individual axons.
Solution Approach 2:
The cuff incorporates elastic or shape-memory materials that allow dynamic, gradual reshaping of the nerve over time rather than immediate rigid deformation. This dynamic approach enables the nerve and axons to adapt progressively to the flattened configuration, minimizing mechanical stress and preventing damage while achieving the desired selective addressability.
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
The FOCI enables precise and efficient optical stimulation of axons across the reshaped fascicle, staying within safety limits and improving the specificity of axon addressing, while also allowing for closed-loop feedback and multi-wavelength stimulation, thus overcoming the limitations of existing optogenetic methods.
Implementation Method 1
The collar member includes a material that exerts a force on the nerve fascicle that will cause the fascicle to gradually reshape to the internal configuration of opening
Implementation Method 2
The optical sources are configured to emit pulsed light to penetrate the reshaped nerve fascicle from one or opposing sides to stimulate axons
Data Source
AI summary
A flat optogenetic cuff interface (FOCI) is configured for functional optical stimulation of axons in a single fascicle of a peripheral nerve bundle in which the axons have been genetically modified to express light sensitive proteins for excitation or inhibition of the nerves. The FOCI is configured to gradually reshape the single fascicle to a final height between 0.2 mm and 0.5 mm by reorganizing the individual axons within the fascicle without reshaping (and damaging) the individual axons. The FOCI facilitates stimulation of axons over the entire cross-section of the reshaped fascicle within the power limitations for pulsed laser energy. An electrical interface may be included to sense nerve activity of either the stimulated axons to provide closed-loop feedback to control the optical sources or stimulated axons of a different modality to record the response. The FOCI may be used as an interface for prosthetic devices to restore lost sensory or motor function, to augment human sensor or motor performance or to modulate autonomic functions.