pH Modifying Contact for Non-Enzymatic Glucose Sensing
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Solution Overview
Problem
Current continuous glucose monitoring devices using enzymatic sensors have a short lifespan due to enzymatic activity degradation, and non-enzymatic metal oxide sensors are limited by requiring high pH environments, which is not compatible with neutral bodily fluids like sweat and tears.
Innovation Solution
A non-enzymatic sensing device with a pH modifying contact that absorbs and expels hydrogen ions in response to applied voltages, allowing for an electrically controllable change in pH to enhance glucose detection at a sensor contact without enzymes, enabling operation in neutral fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If metal oxide sensors are used for non-enzymatic glucose detection, then sensor lifetime is improved, but the sensor can only function at high pH (>10) which is incompatible with neutral bodily fluids (pH=7)
Solution Approach 1:
The patent introduces a pH modifying contact that creates a localized high pH environment (pH>10) around the metal oxide sensor contact, while the bulk fluid remains at neutral pH (pH=7). This local quality change allows the sensor to function in neutral bodily fluids by creating a microenvironment with the required alkaline conditions for metal oxide catalysis.
Solution Approach 2:
The pH modifying contact acts as an intermediary between the neutral bodily fluid and the metal oxide sensor. It absorbs hydrogen ions from the neutral fluid to generate the high pH conditions required by the metal oxide catalyst, thereby mediating the incompatibility between neutral pH fluids and alkaline-requiring sensors.
2Adaptability or versatility
If enzymatic sensors are used for glucose detection in neutral fluids, then pH compatibility is improved, but sensor lifetime deteriorates due to enzymatic activity degradation (1-2 weeks)
Solution Approach 1:
The patent replaces the disposable enzymatic component with a durable metal oxide-based sensor system. While enzymatic sensors require replacement every 1-2 weeks due to enzyme degradation, the metal oxide sensor with pH modification provides a long-lived alternative that does not rely on biological components, effectively eliminating the short lifetime problem.
3Adaptability or versatility
If pH modifying contact is added to enable metal oxide sensing in neutral fluids, then device complexity increases, but this enables operation in sweat and tears
Solution Approach 1:
The patent combines the pH modifying contact and the metal oxide sensor contact into a single integrated sensing device. Both contacts are disposed on the same substrate and work together as a unified system, where the pH modifying contact enables the metal oxide sensor to function in neutral fluids without requiring separate external pH control systems.
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 achieves stable and prolonged glucose detection in neutral bodily fluids, overcoming the limitations of enzymatic sensor lifespans and pH compatibility issues, with the ability to detect glucose concentrations from 0.2 mM to 10 mM in sweat and tears.
Implementation Method 1
a pH modifying contact which includes a material that absorbs hydrogen ions from and expels hydrogen ions to a fluid when in use in response to applied voltages resulting in an electrically controllable change of pH of the fluid
Implementation Method 2
Metal oxide sensors detect glucose via the oxidation reaction of glucose with an activated metal oxide contact; the reaction results in an electron transfer to the contact which is recorded by the sensor as a current
Implementation Method 3
the oxidation reaction of glucose with an activated metal oxide contact; the reaction results in an electron transfer to the contact which is recorded by the sensor as a current
Data Source
AI summary
A non-enzymatic sensor includes a substrate; a sensor contact disposed on the substrate; and a pH modifying contact disposed on the substrate proximate the sensor contact. The pH modifying contact includes a material that absorbs hydrogen from and expels hydrogen to a fluid when in use in response to applied voltages resulting in an electrically controllable change of pH of the fluid. The pH modifying contact is positioned relative to the sensor contact such that the electrically controllable change of pH of the fluid results in a change in pH of the fluid proximal to the sensor contact to thereby enhanced detection of a substance of interest at the sensor contact without the use of enzymes.