Boron Doped Diamond Sensor for In Vivo pH and Oxygen Monitoring
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Solution Overview
Problem
Existing diamond-based electrochemical sensors face interference from dissolved oxygen, particularly when measuring low concentrations of target species, and require external reference electrodes that can drift or be incompatible for in vivo use.
Innovation Solution
A boron doped diamond sensor with non-diamond carbon sites functionalized for redox peaks, allowing for internal pH measurement using the dissolved oxygen peak as a reference, eliminating the need for a standard reference electrode and enabling simultaneous measurement of pH, oxygen, and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-diamond carbon sites are introduced to enable sensing of certain target species, then the sensor can detect species like oxygen and chlorine, but dissolved oxygen interferes with the measurement of target species
Solution Approach 1:
The sensor surface is segmented into distinct functional zones: non-diamond carbon sites for target species detection and diamond sites for dissolved oxygen detection. This spatial segmentation allows simultaneous measurement of both target species and dissolved oxygen without mutual interference, as each zone independently detects its specific analyte.
Solution Approach 2:
Dissolved oxygen measurement serves as an intermediary mechanism to correct target species measurements. By measuring dissolved oxygen at diamond sites and using this information to compensate for interference at non-diamond carbon sites, the system indirectly eliminates the harmful effect of dissolved oxygen on target species detection.
2Measurement precision
If standard reference electrodes are used for pH measurement, then pH can be measured, but the reference electrodes can drift and are incompatible for in vivo use
Solution Approach 1:
The sensor uses its own diamond sites to generate an internal reference signal based on dissolved oxygen reduction. This self-generated reference eliminates dependence on external reference electrodes, allowing the sensor to self-correct pH measurements without drift or biocompatibility issues. The diamond sites serve both as sensing elements and as internal reference generators.
Solution Approach 2:
The diamond sites perform multiple functions: detecting dissolved oxygen, providing an internal reference for pH measurement, and serving as a stable electrochemical platform. This multi-functionality replaces the need for separate reference electrodes and enhances both measurement precision and reliability in vivo.
3Reliability
If high boron content is introduced to achieve desired electrical conductivity, then the diamond material becomes conductive, but significant sp2 carbon is introduced which creates background currents
Solution Approach 1:
The sensor exploits local quality differences between non-diamond carbon regions and diamond regions. Non-diamond carbon sites provide the necessary electrochemical activity for target species detection, while diamond regions provide low background current and high conductivity. By spatially separating these qualities, the system achieves both good conductivity and low background interference.
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 approach provides accurate, real-time, and biocompatible monitoring of pH, oxygen, and temperature without external reference electrodes, suitable for in vivo applications and industrial sensing, reducing interference and electrode drift issues.
Implementation Method 1
electrochemically active non-diamond carbon surface groups bonded to the non-diamond carbon sites for generating a first redox peak at a first potential associated with dissolved oxygen and a second redox peak at a second potential which changes with pH
Implementation Method 2
Diamond can be doped with boron to form semi-conductive or metal like conductive material for use as an electrode
Implementation Method 3
The exceptionally thermal conductivity of the diamond material allows for an accurate and responsive temperature measurement of fluid in contact with the boron doped diamond electrode
Data Source
AI summary
An electrochemical sensor comprising a boron doped diamond electrode formed of boron doped diamond material, an array of non-diamond carbon sites disposed on a sensing surface of the boron doped diamond electrode, electrochemically active non-diamond carbon surface groups bonded to the non-diamond carbon sites for generating a first redox peak at a first potential associated with dissolved oxygen and a second redox peak at a second potential which changes with pH, the first and second redox peaks being separated such that they do not overlap, an electrical controller configured to scan the boron doped diamond electrode over a potential range to generate at least said first redox peak, and a processor configured to give an electrochemical reading based on one or both of a position and an intensity of said first redox peak.