Osmotic Pressure Correction in Chemo-Optical Sensor Spots
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Solution Overview
Problem
Current transcutaneous CO2 sensors face inaccuracies due to osmotic imbalances, leading to sensitivity changes that require time-consuming recalibration, making them unreliable for continuous monitoring, especially in unbalanced osmotic environments.
Innovation Solution
A method using two luminescent dyes with different decay times, where the reference dye is insensitive to gas concentration, allowing for correction of sensitivity changes by measuring its luminescent amplitude, enabling accurate gas concentration determination without recalibration, even in varying osmotic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transcutaneous CO2 sensors are used in unbalanced osmotic environments, then the sensor can operate in diverse conditions, but sensitivity changes occur leading to measurement inaccuracies
Solution Approach 1:
A reference dye is introduced as an intermediary element that does not respond to CO2 but responds to osmotic changes. This reference dye serves as a mediator to detect and compensate for osmotic-induced sensitivity changes in the indicator dye, allowing the sensor to maintain measurement accuracy across diverse osmotic conditions without requiring recalibration
2Measurement precision
If sensor sensitivity is maintained through recalibration, then measurement accuracy is preserved, but continuous monitoring is disrupted by time-consuming recalibration procedures
Solution Approach 1:
The sensor system performs self-correction by using the reference dye to automatically detect and compensate for its own sensitivity changes. The measured value from the reference dye is used to calculate a correction factor that is applied to the indicator dye signal, enabling the sensor to maintain accuracy continuously without external recalibration intervention
Solution Approach 2:
A feedback mechanism is established where the reference dye continuously monitors osmotic conditions and provides information about sensitivity changes. This feedback is processed to generate correction factors that are continuously applied to the CO2 measurement, creating a closed-loop system that maintains measurement precision without time-consuming recalibration steps
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 allows for continuous, accurate monitoring of CO2 concentrations by compensating for osmotic-induced sensitivity changes, ensuring reliable measurements without the need for recalibration, thus improving the stability and usability of transcutaneous CO2 sensors.
Implementation Method 1
using at least two luminescent dyes, the first being in-sensitive to the concentration of a gas with respect to the luminescence response (reference dye) and the second being sensitive to the concentration of a gas with respect to the luminescence response (indicator dye), wherein said dyes show different luminescence decay times
Implementation Method 2
Correction for osmotic pressure variations in chemo-optical sensor spots
Data Source
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AI summary
The present invention relates to a method for optically determining the concentration of a gas, using at least two luminescent dyes, the first being in-sensitive to the concentration of a gas with respect to the luminescence response (reference dye) and the second being sensitive to the concentration of a gas with respect to the luminescence response (indicator dye), wherein said dyes show different luminescence decay times so that the resultant phase angle is indicative for the concentration of a gas, characterized in that the detected luminescent amplitude of the reference dye at a first moment in time is utilized to correct for sensitivity changes after said moment. The present invention also relates to a corresponding method for quality assessment of the measurement of an optical sensor for determining the concentration of a gas.