Ionic Liquid Gate Oxygen Sensor for Dissolved Blood Analysis
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Solution Overview
Problem
Existing oxygen sensors for dissolved oxygen in liquids, such as blood, are costly and bulky due to the requirement of precious metal electrodes and complex electrochemical cells, and lack specificity for oxygen measurement.
Innovation Solution
An oxygen sensing device utilizing an ionic liquid gate-induced oxygen ion motion across an oxide film, which changes conductivity in response to oxygen concentration, eliminating the need for precious metals and enabling a compact, portable sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polarography with precious metal electrodes and electrochemical cells is used, then oxygen measurement precision is achieved, but device cost and size increase
Solution Approach 1:
The patent extracts the oxygen sensing function from the complex electrochemical cell structure and implements it directly in the oxide film layer. By removing the need for separate reference electrodes and complex cell assemblies, the invention achieves oxygen measurement while significantly simplifying the device structure and reducing costs.
Solution Approach 2:
The patent replaces the mechanical/electrochemical system requiring precious metal electrodes and liquid electrolytes with a solid-state oxide film-based system. This substitution eliminates complex mechanical assemblies while maintaining measurement precision through electrical conductivity changes in the oxide film.
2Measurement precision
If polarography with electrochemical cells is used, then oxygen measurement is achieved, but device size increases
Solution Approach 1:
The patent extracts the oxygen sensing function from the bulky electrochemical cell and integrates it into a thin oxide film layer. This extraction eliminates the need for large reference electrode assemblies and liquid electrolyte containers, achieving precise oxygen measurement in a compact form factor suitable for portable applications.
Solution Approach 2:
The patent employs a thin oxide film as the sensing element, replacing the bulky electrochemical cell structure. This thin-film approach enables precise oxygen measurement while dramatically reducing device volume, making the sensor suitable for portable and implantable applications.
3Reliability
If ionic liquid gating is applied to oxide films, then conductivity changes occur, but oxygen must be removed from the film interior
Solution Approach 1:
The patent introduces an ionic liquid as an intermediary medium between the gate electrode and the oxide film. This ionic liquid mediator enables efficient charge transfer and facilitates oxygen ion extraction from the film interior, achieving reliable conductivity control while simplifying the overall device structure compared to direct solid-state gating approaches.
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 precise and cost-effective measurement of dissolved oxygen with high specificity to oxygen, reducing size and operational costs while maintaining sensitivity and accuracy.
Implementation Method 1
The voltage gating of an ionic liquid (IL) at the surface of an oxide film can create an electric field large enough that oxygen migrates from within the interior of the film to its surface
Implementation Method 2
oxygen migrates from within the interior of the film to its surface... This process is reversible and can be used with a large class of oxides having channels through which oxygen ions migrate
Implementation Method 3
One consequence of the IL gating is the change in conductivity of the oxide films... The observed conductivity increase of the insulating state upon IL gating (application of positive gate voltage) is roughly three orders of magnitude
Data Source
AI summary
An apparatus includes an oxide layer having ion transport channels that facilitate the migration of oxygen ions from a first side to a second side of the layer. Specifically, molecular oxygen is decomposed into oxygen ions at the first side, and oxygen ions recombine into molecular oxygen at the second side. The apparatus includes a first chamber having a polarizable medium located on the second side of the oxide layer; a second chamber having an analyte that includes dissolved oxygen is located on the first side. The apparatus further includes a gate electrode that is in contact with, and applies a voltage to, the polarizable medium; in this manner, an electric field is applied to the second side of the oxide layer, which drives oxygen ions across the oxide layer. The apparatus can be used as an oxygen sensor, e.g., for detecting oxygen in a liquid such as blood.