Diffusion-Resistance Membrane for Low-Drift Glucose Sensors
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Solution Overview
Problem
Existing analyte sensors face issues with sensor drift due to changes in permeability and interference from external molecules, leading to non-linear responses and sensitivity fluctuations, especially when analyte concentrations exceed sensor sensitivity limits.
Innovation Solution
Development of a diffusion-resistance layer using polymers with a glass transition temperature above −50°C and ultimate tensile strength above 6000 psi, incorporating base polymers like polyurethane and hydrophilic polymers, which stabilize the membrane structure and reduce sensor drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a semipermeable membrane is used to control analyte diffusion, then sensor linearity is improved, but sensor drift occurs due to changes in membrane permeability over time
Solution Approach 1:
The patent employs composite polymer materials combining hydrophilic polymers (like polyethylene oxide) with hydrophobic polymers (like polyurethane) to create a diffusion-resistance layer that maintains stable permeability. This composite structure provides both the necessary analyte diffusion control for linearity and structural stability to prevent drift over time.
Solution Approach 2:
The patent specifies precise parameter ranges for the base polymer, including glass transition temperature (greater than −50°C) and ultimate tensile strength (greater than 6000 psi), to ensure the membrane maintains its physical and chemical properties stable over time, thereby preventing permeability changes that cause drift while still allowing controlled diffusion for linearity.
2Reliability
If the membrane structure is made more stable to reduce drift, then sensor reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent defines specific parameter ranges for base polymers (glass transition temperature > −50°C, ultimate tensile strength > 6000 psi) that balance structural stability for reduced drift with manufacturability. These parameter specifications guide material selection without requiring overly complex manufacturing processes.
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 solution provides sensors with less than 10% drift over 10 days, ensuring stable and continuous analyte concentration measurement, particularly for glucose, by maintaining a structurally stable matrix and minimizing interference.
Implementation Method 1
there is a membrane layer or domain that is primarily responsible for limiting the diffusion of the analyte to the sensor
Implementation Method 2
a base polymer having a lowest glass transition temperature as measured using ASTM D3418 of greater than −50° C. and an ultimate tensile strength as measured by ASTM D1708 that is greater than 6000 psi
Data Source
AI summary
Disclosed are devices for determining an analyte concentration (e.g., glucose). The devices comprise a sensor configured to generate a signal associated with a concentration of an analyte and a sensing membrane located over the sensor. The sensing membrane comprises an enzyme layer, wherein the enzyme layer comprises an enzyme and a polymer comprising polyurethane and/or polyurea segments and one or more zwitterionic repeating units. The enzyme layer protects the enzyme and prevents it from leaching from the sensing membrane into a host or deactivating.