Ion-Selective Electrode Assembly for Closed-Loop Neural Modulation
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Solution Overview
Problem
Conventional functional electrical stimulation (FES) techniques lack an effective, implantable method for nerve signal simulation and conduction block with high control and compact size, particularly for spinal cord injury and neurological disorders.
Innovation Solution
A prosthetic device with an ion-selective electrode assembly that maintains a predetermined ion concentration near nerve cells using a closed-loop system, allowing for precise modulation of ion concentrations through potentiometric measurement and controlled electric current application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional FES techniques are used for nerve stimulation, then motor activity can be restored, but the control precision and compactness are insufficient
Solution Approach 1:
The patent changes the fundamental parameter of neural modulation from direct electrical stimulation to electrochemical modulation via ion concentration control. By controlling the concentration of ions (such as K+, Na+, Ca2+) in the extracellular space, the device achieves precise control over nerve excitability thresholds, allowing for differentiated stimulation and blocking effects with high spatial and temporal precision.
Solution Approach 2:
The patent introduces ion-selective membranes as intermediary components between the electrode and the nerve tissue. These membranes selectively transport specific ions to the nerve surface, creating a controlled chemical environment that modulates nerve excitability. This intermediary approach enables precise control while maintaining a compact device structure, as the membranes are thin and can be integrated directly onto electrode surfaces.
2Measurement precision
If ion concentration modulation is used for neural activity control, then precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the electrode and ion-selective membrane into a single integrated component called an ion-selective electrode assembly. The membrane is deposited directly onto the electrode surface, combining the electrical stimulation function with the ion-selective transport function in one compact unit. This integration eliminates the need for separate membrane chambers or complex delivery mechanisms, maintaining concentration control accuracy while reducing overall device complexity.
Solution Approach 2:
The patent employs thin-film ion-selective membranes that can be directly applied to electrode surfaces. These thin films provide the necessary ion-selective functionality without adding significant bulk or complexity to the device. The membranes are sufficiently thin to allow efficient ion transport while maintaining structural integrity and ease of integration into compact implantable devices.
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 device provides improved concentration control and accuracy in modulating neural activity, enabling targeted nerve stimulation or inhibition, potentially addressing limitations in existing FES techniques.
Implementation Method 1
the ion-selective electrode configuration is configured to sense the concentration of the target ion by potentiometric measurement
Implementation Method 2
Devices with polarizing electrodes modified with ion-selective materials can selectively enrich or deplete the concentration of a targeted ion in a constrained volume around the electrode. By driving current across a membrane filter with single-ion transport selectivity, one can modulate the concentration of a selected ion
Implementation Method 3
By driving current across a membrane filter with single-ion transport selectivity, one can modulate the concentration of a selected ion in the local volume of the membrane-enriching or depleting it depending on the polarity of the current
Data Source
AI summary
A prosthetic device includes a closed loop system for maintaining a predetermined concentration of a target ion in a region in proximity to a cell, such as a nerve cell. The device includes a controller and an ion-selective electrode assembly operatively connected to the controller, wherein the ion-selective electrode configuration is configured to sense the concentration of the target ion by potentiometric measurement and to convey the concentration to the controller. The controller is configured to modulate the current to the ion-selective electrode assembly based on the concentration of the target ion to control the concentration of the target ion so as to maintain the predetermined concentration of the target ion.