Aliphatic Polyurethane Diffusion Barriers for In Vivo Sensors
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Solution Overview
Problem
Existing implantable biosensors face challenges in accurately measuring physiologically relevant analyte concentrations due to issues with diffusion barriers that either limit the measurement range or allow toxic components to elute into the body, and there is a need for a biocompatible membrane that prevents interference and maintains accurate analyte concentration measurements.
Innovation Solution
A sensor device with an electrode system using an aliphatic polyurethane diffusion barrier with a molecular weight cut-off (MWCO) of < 10 kDa, which stabilizes analyte concentration and prevents the passage of toxic components, while maintaining sensitivity over time through controlled manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diffusion barrier is used to extend the measurement range and reduce analyte consumption, then the measurement accuracy is improved, but toxic components may elute into the patient body
Solution Approach 1:
The patent employs a composite membrane structure combining multiple materials with complementary properties: an outer layer for biocompatibility and toxin rejection, and an inner layer for analyte permeability. This composite approach allows the diffusion barrier to simultaneously extend measurement range while preventing toxic component elution into the patient body.
Solution Approach 2:
The membrane is designed with spatially varying properties - different regions have different permeability characteristics tailored to specific functions. The outer surface possesses biocompatible properties to prevent immune response and toxin release, while the inner region maintains high analyte permeability for accurate measurement, thus resolving the contradiction between measurement accuracy and safety.
2Measurement precision
If the diffusion barrier reduces analyte consumption to improve measurement correctness, then the in-vivo concentration accuracy is improved, but the measurement range may be limited
Solution Approach 1:
The patent utilizes controlled changes in membrane parameters including thickness, porosity, and material composition to optimize the balance between analyte consumption reduction and measurement range extension. By adjusting these parameters, the diffusion barrier maintains high analyte concentration accuracy while accommodating a broader range of analyte concentrations.
3Reliability
If screen printing paste components are added to create a functional working electrode, then the electrode functionality is improved, but the paste nature changes substantially
Solution Approach 1:
The patent incorporates all necessary functional components (enzymes, mediators, conductive materials) into the screen printing paste formulation during the manufacturing stage. This preliminary incorporation ensures that the paste maintains its applicability and handling properties while already containing the complete functional electrode system, thus resolving the contradiction between electrode functionality and manufacturing ease.
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 aliphatic polyurethane diffusion barrier effectively extends the measurement range, reduces analyte consumption, and maintains sensor accuracy by stabilizing local analyte concentration, minimizing sensitivity loss over three months and one year.
Implementation Method 1
a diffusion barrier that controls diffusion from the exterior of the electrode system to the immobilized enzyme molecules
Implementation Method 2
The diffusion barrier comprises an aliphatic polyurethane with a molecular weight cut-off (MWCO) of < 10 kDa, which stabilizes analyte concentration and prevents the passage of toxic components
Data Source
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AI summary
The disclosure refers to a sensor device for determining the concentration of an analyte under in-vivo conditions, comprising an electrode system having an electrode with immobilized enzyme molecules and a diffusion barrier that controls diffusion from the exterior of the electrode system to the immobilized enzyme molecules, wherein the diffusion barrier comprises an aliphatic polyurethane. Further, a process of manufacturing a sensor device is provided.