Microfabricated Neurochemical Probe With Separated Sensing Electrodes
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Solution Overview
Problem
Existing microprobe sensors for detecting gamma-amino-butyric acid (GABA) and glutamate (GLU) are limited by their size, which results in greater damage upon insertion and potential sensitivity issues due to the wide spacing of electrodes, leading to cross-contamination.
Innovation Solution
Development of a microfabricated implantable probe with closely spaced neurochemical sensing electrodes, separated by a polymeric layer, and a sentinel electrode to minimize cross-contamination and trauma, allowing for simultaneous and sensitive detection of GABA and GLU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electrode spacing is reduced to minimize probe size and insertion trauma, then insertion trauma is reduced, but cross-contamination between electrodes increases
Solution Approach 1:
The probe structure is segmented into separate chambers or zones for different electrode types (e.g., recording electrodes, stimulation electrodes, reference electrodes). Each electrode type occupies a distinct spatial region, allowing close overall spacing while maintaining functional separation and preventing cross-contamination between electrode signals.
Solution Approach 2:
An intermediary substance or structure is introduced between adjacent electrodes to prevent direct interaction and cross-contamination. This could be an insulating material, a physical barrier, or a chemical separator that allows electrodes to be positioned closely together without signal interference or contamination.
2Reliability
If electrode spacing is increased to avoid cross-contamination, then cross-contamination is reduced, but probe size increases
Solution Approach 1:
Electrodes are arranged in a three-dimensional configuration rather than simple linear spacing. Multiple electrodes can be stacked vertically or positioned at different depths within the probe shaft, allowing close lateral spacing while maintaining sufficient separation in the vertical dimension to prevent cross-contamination.
Solution Approach 2:
Electrodes are nested within concentric structures or layered configurations where inner electrodes are surrounded by outer electrodes or protective structures. This nested arrangement maximizes the use of available space while maintaining proper isolation between different electrode types through the nested structural layers.
3Object-affected harmful factors
If probe size is reduced to minimize insertion trauma, then insertion trauma is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The probe incorporates standardized, modular electrode designs and universal mounting structures that can be manufactured using conventional fabrication techniques. Common structural elements and repeatable patterns reduce the need for high-precision custom manufacturing while maintaining proper electrode alignment and spacing.
Solution Approach 2:
The probe design incorporates adjustable or flexible parameters such as variable electrode spacing, selectable electrode configurations, or compliant mounting structures that can accommodate normal manufacturing tolerances. This flexibility allows the probe to maintain proper function and alignment even with standard manufacturing precision rather than requiring ultra-precise fabrication.
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 probe achieves reliable and sensitive simultaneous detection of GABA and GLU with minimal insertion trauma by ensuring close electrode spacing and using a polymeric separating layer to prevent cross-contamination, maintaining accuracy and reducing tissue damage.
Implementation Method 1
a polymeric separating layer configured to form an alveolae around each sensing electrode and prevent cross-contamination between the sensing electrodes
Implementation Method 2
at least one pair of enzyme-functionalized sensing electrodes disposed on the shaft... the sensing electrodes may be functionalized for neurochemical sensing... functionalized with Gabase and the other with GOx enzyme for the sensing of GABA and GLU respectively
Data Source
AI summary
The disclosure features a microfabricated implantable probe, the probe comprising (a) a semiconductor substrate microprobe body including a handling portion and an elongated shaft extending from the handling portion to a tip, the tip being configured for insertion into a target area of a subject mammal, (b) at least one pair of enzyme-functionalized sensing electrodes disposed on the shaft, (c) individually addressable conductive metallic leads extending for a specified distance from each sensing electrode to contact pads disposed on the handling portion, and (d) a polymeric separating layer configured to separate each sensing electrode in the pair of electrodes from the other sensing electrode. The disclosure also features methods of using the probe to detect neurochemicals.