Bent Micro-Wire Stimulators for Selective Cortical Activation

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Solution Overview

Problem

The long-term viability of implantable cortical electrodes is limited by biological reactions and the spatially symmetric electric fields they induce, leading to diminished effectiveness and unwanted side effects, while magnetic stimulation offers stability but requires larger coils that are not safe for implantation.

Innovation Solution

Micro-wire stimulators with bends are designed to create spatially asymmetric magnetic fields, allowing selective targeting of neural cells with reduced cross-sectional area to minimize trauma and biological response, and are fabricated using biocompatible materials to enhance stability and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional electrodes are used for cortical stimulation, then electrical stimulation can be delivered to modulate CNS neuron activity, but the electrodes induce spatially symmetric electric fields that activate all nearby neuronal targets regardless of orientation, leading to spread of activation beyond the local region and unwanted side effects

Engineering Contradiction:

Improveneural activation effectivenessVSAvoidspread of activation and side effects

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by using bent micro-wire configurations instead of conventional straight or symmetric electrode designs. The bent wires create spatially asymmetric magnetic fields that produce directional electric field gradients, enabling selective activation of neurons with specific orientations while minimizing activation of neurons in other directions. This resolves the contradiction by maintaining stimulation effectiveness for target neurons while reducing unwanted spread of activation to non-target neurons.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If implantable cortical electrodes are used for long-term stimulation, then neural modulation is achieved, but biological reactions occur including activated astrocytes encapsulating electrodes and impedance changes, diminishing stimulation effectiveness over time

Engineering Contradiction:

Improvestimulation effectivenessVSAvoidlong-term viability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the conventional electrical stimulation mechanism with magnetic stimulation using bent micro-wires. This substitution eliminates direct electrical contact between the implant and neural tissue, thereby preventing the biological reactions (astrocyte activation and encapsulation) that occur with traditional electrodes. The magnetic field penetrates tissue without causing the same foreign body response, resolving the contradiction between maintaining reliable stimulation and ensuring long-term viability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If larger coils are used for magnetic stimulation, then magnetic field strength is sufficient for neural activation, but the cross-sectional area increases causing greater trauma and biological response, making implantation unsafe

Engineering Contradiction:

Improvemagnetic field strengthVSAvoidtissue trauma and biological response

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent segments the magnetic stimulation system into multiple small bent micro-wires instead of using a single large coil. Each micro-wire generates a localized magnetic field, and the collective effect of multiple micro-wires provides sufficient overall stimulation power. This segmentation allows the system to maintain adequate magnetic field strength for neural activation while keeping each individual wire small enough to minimize tissue trauma and biological response, resolving the contradiction between power requirements and safety.

Inventive Principle:

Principle #1Segmentation

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 micro-wire stimulators effectively and selectively activate specific neural populations with reduced side effects, maintaining consistency over time and comparable efficacy to electrode-based stimulation, while minimizing tissue reaction and trauma.

Implementation Method 1

The micro-wire stimulator design utilizes one or more bends in the micro-wire to enhance the strength of the induced field

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11007372B2Selective activation of cortex using bent micro wires to magnetically stimulate neurons

Publication Date: 2021.05.18 THE GENERAL HOSPITAL CORP

AI summary

Disclosed are micro-wire stimulators that magnetically stimulate nearby cells and/or their processes (e.g., nerve fiber, axons, dendrites, etc.). The micro-wire includes one or more bends. The micro-wire stimulator can facilitate the creation of stronger field gradients in one direction with much smaller gradients in orthogonal directions, allowing for selective targeting, or avoiding, of specific cell types within a targeted region. The bent micro-wire stimulator may be implanted into the cortex of the brain to selectively stimulate nearby neural cells having a particular orientation relative to the stimulator. A tip portion of the micro-wire may be rounded, or it may have corners forming other suitable geometric shapes.