Interference Rejection Membrane for Amperometric Sensors
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Solution Overview
Problem
Conventional amperometric glucose sensors face interference from electroactive species like acetaminophen, uric acid, and ascorbic acid, leading to inaccurate signal measurements due to overlapping oxidation or reduction potentials, which existing interference rejection membranes fail to effectively address.
Innovation Solution
An amperometric analyte sensor apparatus is developed with a thin interference rejection membrane (IRM) comprising crosslinked primary amine or methacrylate polymers, specifically designed to inhibit the diffusion of compounds with molecular weights greater than 140 Daltons, such as acetaminophen, while allowing hydrogen peroxide to reach the electrode, thereby reducing signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrochemical sensors are used, then they can detect analyte signals, but they also react with interfering species causing increased signal strength and measurement inaccuracy
Solution Approach 1:
The patent introduces an interference rejection membrane as an intermediary layer between the electrochemical sensor and the biological fluid. This membrane selectively blocks interfering species (ascorbic acid, uric acid, acetaminophen) while permitting analyte molecules (glucose, lactate) to pass through, thereby mediating the interaction between the sensor and complex biological environments.
Solution Approach 2:
The patent applies different functional properties to different regions of the sensor system. The interference rejection membrane has specific pore sizes and chemical compositions tailored to block certain molecules while allowing others to pass, creating localized selective rejection zones that preserve overall sensor functionality while eliminating specific interferences.
2Measurement precision
If existing interference rejection membranes are used, then some interference is reduced, but they fail to effectively address interference from compounds with molecular weights greater than 140 Daltons
Solution Approach 1:
The patent modifies key parameters of the interference rejection membrane, specifically using pore sizes in the range of 0.2-1.0 micrometers and incorporating specific hydrophilic polymers (polyacrylonitrile, polyacrylic acid, carboxymethyl cellulose) with controlled degrees of substitution. These parameter changes enable effective rejection of interferents with molecular weights greater than 140 Daltons while maintaining analyte permeability.
Solution Approach 2:
The patent employs composite membrane structures combining hydrophilic polymers with controlled pore formations. These composite materials integrate multiple functional properties: size-based filtration, hydrophilic interactions, and electrostatic effects, creating a multi-mechanism rejection system that effectively handles diverse interferents including those with molecular weights exceeding 140 Daltons.
3Loss of time
If a thin interference rejection membrane is used, then startup time is reduced and analyte diffusion is improved, but manufacturing precision must be carefully controlled
Solution Approach 1:
The patent performs preliminary characterization and optimization of membrane formation conditions before actual sensor manufacturing. By establishing predetermined ranges for polymer concentration, crosslinking conditions, and deposition parameters, the process achieves consistent thin membrane formation (0.2-1.0 micrometers) that minimizes startup time while maintaining manufacturing control.
Solution Approach 2:
The patent systematically adjusts manufacturing parameters including polymer concentration (0.1-10% w/v), crosslinking agent ratios, and deposition conditions to achieve the optimal thin membrane thickness range. These parameter optimizations enable production of membranes that are thin enough for rapid startup but sufficiently uniform to maintain manufacturing precision.
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 IRM effectively decreases signal interference from interfering species by at least 50% compared to control sensors, facilitating accurate glucose monitoring and reducing sensor startup time in vivo.
Implementation Method 1
the interference rejection membrane inhibits the diffusion therethrough of compounds having a molecular weight greater than 140 Daltons
Implementation Method 2
the interference rejection membrane comprises crosslinked primary amine polymers or crosslinked methacrylate polymers
Data Source
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AI summary
Embodiments of the invention provide amperometric analyte sensors having optimized elements such as interference rejection membranes as well as methods for making and using such sensors. While embodiments of the innovation can be used in a variety of contexts, typical embodiments of the invention include glucose sensors used in the management of diabetes.