Implantable Analyte Sensor Protection Using Multiple Metals
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Solution Overview
Problem
Implanted sensors used to measure analytes in living animals face degradation due to inflammation reactions and foreign body responses, particularly from reactive oxygen species like hydrogen peroxide, which shorten their longevity.
Innovation Solution
A sensor system incorporating a protective material with multiple metals, such as Cu, W, Pt, Fe, Mo, and their oxides or alloys, that catalytically decompose or inactivate reactive species, thereby reducing degradation and extending the sensor's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor is implanted in the body of a living animal, then the sensor can measure analytes in vivo, but the animal's immune system attacks the sensor and degrades the indicator molecules through reactive oxygen species
Solution Approach 1:
A protective layer comprising metal particles (such as platinum, copper, or their alloys) is introduced as an intermediary between the indicator molecules and the hostile biological environment. This protective layer catalytically decomposes reactive oxygen species like hydrogen peroxide into water and oxygen, preventing direct contact and degradation of the indicator molecules while allowing the sensor to function reliably in vivo
2Measurement precision
If the sensor uses indicator molecules with boronate groups to bind glucose, then the sensor can detect glucose levels, but hydrogen peroxide oxidizes the boronate group and disables glucose binding
Solution Approach 1:
The protective layer with metal particles is positioned and activated in advance to neutralize hydrogen peroxide before it can reach and oxidize the boronate groups of the indicator molecules. This preliminary protective action prevents the harmful oxidation reaction from occurring, preserving the boronate group's glucose-binding capability and maintaining measurement precision over time
3Device complexity
If no protective material is used, then the sensor structure remains simple, but the indicator molecules degrade rapidly due to inflammation reactions and foreign body response
Solution Approach 1:
The sensor employs a composite structure where metal particles (platinum, copper, or their alloys) are integrated into a protective layer that is applied over the indicator molecules. This composite protective layer combines the catalytic properties of metals with a supporting matrix material, creating a multi-functional barrier that extends sensor longevity while maintaining a relatively simple overall device architecture
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 use of multiple metals in the protective system effectively reduces analyte indicator degradation, leading to increased sensor longevity and improved in vivo functionality.
Implementation Method 1
The protective material can include metals, metal complexes, or metal oxides which catalytically decompose or inactivate in vivo reactive species or biological oxidizers
Implementation Method 2
Hydrogen peroxide may degrade the indicator molecules by oxidizing the boronate group, thus disabling the ability of the indicator molecule to bind glucose
Data Source
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AI summary
A sensor (e.g., an optical sensor) that may be implanted within a living animal (e.g., a human) and may be used to measure an analyte (e.g., glucose or oxygen) in a medium (e.g., interstitial fluid, blood, or intraperitoneal fluid) within the animal. The sensor may include a sensor housing, an analyte indicator covering at least a portion of the sensor housing, and a multiple metal protective system including multiple metals incorporated in and/or in close proximity to a surface of the analyte indicator that reduce deterioration of the analyte indicator.