Electrochemical Sensor Electrode Pad Edge Insulation
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Solution Overview
Problem
Electrochemical sensors for long-term monitoring of analytes in body tissues face challenges due to mechanical and chemical stress, leading to delamination of metal electrodes from the substrate, which affects their stability and accuracy.
Innovation Solution
The electrochemical sensor design includes a substrate with a proximal and distal part, featuring working, reference, and counter electrodes with a corrosive conductive layer covered by a non-corrosive layer, and an insulating layer that overlaps the electrode pad edges or has an elongated shape to reduce mechanical stress and protect against oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal electrode layer is used for electrical connection, then electrical conductivity is improved, but the electrode becomes susceptible to oxidation and mechanical stress leading to delamination
Solution Approach 1:
A non-corrosive conductive layer is introduced as an intermediary between the corrosive metal electrode layer and the body fluid environment. This intermediate layer protects the metal electrode from oxidation and mechanical stress while maintaining electrical conductivity, thus resolving the contradiction between electrical performance and chemical stability.
Solution Approach 2:
The electrode structure is designed as a composite material system combining a corrosive conductive layer (for electrical conductivity) with a non-corrosive conductive layer (for protection). This composite structure integrates the advantages of both materials: the metal provides excellent electrical properties while the protective layer provides oxidation resistance and mechanical stability.
2Duration of action of stationary object
If the sensor is designed for long-term implantation, then monitoring duration is improved, but mechanical stress and delamination risk increase
Solution Approach 1:
The non-corrosive conductive layer acts as a protective intermediary that shields the electrode structure from mechanical stress and chemical degradation during long-term implantation. This intermediate protection layer enables extended monitoring duration by preventing delamination and maintaining structural integrity under physiological conditions.
Solution Approach 2:
The protective non-corrosive conductive layer is applied in advance to cushion and absorb mechanical stresses before they can damage the underlying metal electrode layer. This preliminary protection enables the sensor to withstand long-term implantation stresses without delamination.
3Object-affected harmful factors
If a protective layer is added to prevent oxidation, then chemical stability is improved, but device complexity increases
Solution Approach 1:
The protective non-corrosive conductive layer is applied specifically to the electrode surfaces where oxidation and mechanical stress occur, rather than coating the entire sensor. This localized protection approach provides necessary chemical stability while minimizing overall device complexity and maintaining manufacturing simplicity.
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 design enhances the mechanical and chemical stability of the sensor, reducing the risk of delamination and improving long-term monitoring accuracy by shielding the electrodes from stress and oxidation.
Implementation Method 1
the corrosive conductive layer comprises at least one metal being less noble or as noble as Ag, wherein the non-corrosive conductive layer comprises at least one metal being more noble than Ag
Implementation Method 2
an insulating layer is disposed on the substrate leaving openings in the area of the electrode pads... the insulating layer at least partially overlaps on at least one electrode pad edge
Implementation Method 3
the electrically conductive sensor material comprises at least one detector substance adapted to perform an electrically detectable electrochemical detection reaction with the analyte
Data Source
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AI summary
An electrochemical sensor (110) is disclosed, specifically for detecting an analyte in a body fluid, more specifically an electrochemical sensor for insertion of a body tissue of the user. The electrochemical sensor (110) comprises a substrate (112) having a proximal part (114) and an elongated distal part (118). At least one working electrode (124), at least one reference electrode (128) and at least one counter electrode (134)are formed on the distal part (118). The working electrode (124) comprises a conductive trace (174, 198)along which multiple electrode pads (142) are arranged that are connected via the conductive trace (174, 198). The electrode pads (142) include a corrosive conductive layer (144) covered by a non-corrosive conductive layer (146). An insulating layer (138) is disposed on the substrate (112) leaving openings (164) in the area of the electrode pads (142). The electrochemical sensor (110) comprises at least one protective measure for the corrosive conductive layer (144) selected from the group consisting of: a.the insulating layer (138) at least partially overlaps on at least one electrode pad edge (170) of at least one of the electrode pads (142); b.at least one of the electrode pads (142) has an elongated shape along the smaller dimension of the elongated distal part (118).