Sterilized Optical Analyte Sensor with Fluorescence Correction

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Solution Overview

Problem

Current analyte sensors face challenges in maintaining sterility and accuracy during manufacturing, packaging, and calibration, especially after sterilization processes like gamma irradiation, which can affect chemical detection systems, and there is a need for continuous and accurate monitoring of blood glucose levels in critical care settings.

Innovation Solution

A continuous glucose monitoring system that incorporates an analyte sensor with a controller capable of converting fluorescent emission signals into electrical signals, allowing for real-time monitoring, calibration, and correction for temperature and pH effects, using a microcontroller and optical subassembly with LEDs and photodiode detectors to provide accurate glucose concentration measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sterilization processes like gamma irradiation or ethylene oxide are used to ensure sensor sterility, then the sensor achieves required sterility levels, but the chemical detection system (fluorophores) is affected and measurement accuracy deteriorates

Engineering Contradiction:
Improvesensor sterilityVSAvoidglucose measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-determining sterilization correction factors during the manufacturing process. The sensor is exposed to sterilization conditions (gamma irradiation or ethylene oxide) in a controlled environment, and the resulting changes in fluorophore emission are measured and stored as correction factors in memory. This allows the sensor to be pre-compensated for sterilization effects before clinical use, resolving the contradiction between achieving sterility and maintaining measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If information is programmed or read-written to sensor memory after sterilization processing, then the sensor can perform real-time monitoring functions, but the sensor is exposed to atmosphere which compromises sterility

Engineering Contradiction:
Improvesensor programming capabilityVSAvoidsensor sterility
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses an intermediary approach by introducing a sterile connector system that allows programming and data transfer without breaching sterility. The connector includes a sterile interface that can be mated with external programming devices through a sterile barrier, enabling information to be written to or read from the sensor memory while the sensor remains in a sterile, sealed package until the moment of use.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the sensor operates based on chemical detection system (fluorophores) for real-time glucose monitoring, then continuous monitoring capability is achieved, but the system becomes sensitive to sterilization process effects

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoidsterilization process sensitivity
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback by continuously monitoring the fluorophore emission signal and comparing it against reference values stored in memory. The system includes a processor that analyzes the emission signal, applies the pre-determined sterilization correction factors, and compensates for any drift or changes in fluorophore performance. This feedback mechanism ensures that continuous monitoring accuracy is maintained despite the inherent sensitivity of the chemical detection system to sterilization processes.

Inventive Principle:
Principle #23Feedback

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

Enables continuous, accurate, and reliable monitoring of blood glucose levels, ensuring glycemic control by correcting for sterilization effects and environmental factors, thereby improving patient safety and clinical outcomes.

Implementation Method 1

an analyte sensor with a controller capable of converting fluorescent emission signals into electrical signals

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

optical subassembly with LEDs and photodiode detectors

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2751577B1A method of manufacturing a sterilized optical analyte sensor
Publication Date: 2019.04.17 MEDTRONIC MINIMED INC
  • EP2751577B1 patent drawingFigure 1
  • EP2751577B1 patent drawingFigure 2
  • EP2751577B1 patent drawingFigure 3

AI summary

Embodiments are directed to a system for detecting blood analyte concentration. The system may comprise a chemical indicator system and optical emitters, fibers, and detectors. The system may also comprise various algorithms to measure and improve the optical signal. The system may also comprise a controller configured to adjust the excitation pulse character based on the physiological measurements and/or to extend the duration of the chemical indicator system.