Lactate Sensor Membrane Chemistry for Stable High-Sensitivity Detection

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Solution Overview

Problem

Existing lactate-responsive analyte sensors suffer from poor sensitivity and instability, limiting their diagnostic value, despite efforts to stabilize the sensor response with catalase and improve mass transport limiting membranes.

Innovation Solution

Incorporation of human serum albumin as a stabilizer in combination with specific membrane chemistries, such as polyethylene glycol-crosslinked polyvinylpyridine homopolymers or copolymers, to enhance sensitivity and stability of lactate detection in lactate-responsive analyte sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If lactate oxidase is used to replace glucose oxidase in glucose-responsive analyte sensors, then the sensor can detect lactate levels, but the sensitivity and response stability deteriorate

Engineering Contradiction:

Improveanalyte detection capabilityVSAvoidsensitivity and response stability

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces human serum albumin as an intermediary stabilizing agent that mediates between lactate oxidase and the sensor matrix. This intermediary protein protects lactate oxidase from denaturation and maintains its catalytic activity, thereby improving sensitivity and response stability while preserving lactate detection capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the sensor composition by incorporating specific concentrations of human serum albumin (0.1-10 mg/mL) and adjusting pH conditions (pH 6.0-8.0) to optimize lactate oxidase stability. These parameter changes transform the unstable lactate-responsive sensor into a stable diagnostic tool with extended response stability over several days

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a mass transport limiting membrane is added to improve analyte flux control, then sensor overload is avoided, but the overall sensor response sensitivity decreases

Engineering Contradiction:

Improvesensor overload preventionVSAvoidanalyte sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent employs a thin film mass transport limiting membrane with optimized thickness (5-50 nm) that provides sufficient protection against sensor overload while maintaining high lactate permeability. This thin film approach balances the conflicting requirements of reliability and sensitivity by allowing adequate analyte flux while preventing saturation

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite membrane structure combining hydrophilic polymers (e.g., polyethylene glycol, polyvinylpyridine) with crosslinking agents to form a porous network that selectively transports lactate. This composite material approach achieves both overload protection and high sensitivity through controlled porosity and chemical composition

Inventive Principle:

Principle #40Composite materials

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 combination achieves high sensitivity and extended response stability, allowing for reliable lactate monitoring over several days, suitable for diagnostic applications.

Implementation Method 1

The active area comprises a polymer, human serum albumin, and a lactate-responsive enzyme covalently bonded to the polymer

Methodology Applied

Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 2

Lactate-responsive analyte sensors generally display inferior performance for assaying lactate using similar sensing chemistry

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

the membrane may be permeable or semipermeable to an analyte of interest and limit the overall analyte flux to the active area of the analyte sensor

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 4

the membrane may be permeable or semipermeable to an analyte of interest

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 5

Methodology Applied

Scientific EffectProtein stabilization:

Implementation Method 6

polyethylene glycol-crosslinked polyvinylpyridine homopolymers or copolymers

Methodology Applied

Scientific EffectCrosslinking:

Implementation Method 7

the mass transport limiting membrane may comprise at least a crosslinked polyvinylpyridine homopolymer or copolymer

Methodology Applied

Scientific EffectPolymer network formation:

Data Source

PatentEP3781034B1Lactate sensors and associated methods

Publication Date: 2025.12.31 ABBOTT DIABETES CARE INC

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AI summary

A lactate-responsive enzyme may form the basis for lactate detection and quantification using an electrochemical analyte sensor. Various features may be incorporated within an analyte sensor containing a lactate-responsive enzyme, particularly lactate oxidase, to improve sensitivity and response stability of the analyte sensor. Such analyte sensors may comprise: a working electrode having an active area disposed thereon, and a mass transport limiting membrane overcoating at least the active area upon the working electrode. The active area comprises at least a polymer, an albumin, and a lactate-responsive enzyme that is covalently bonded to the polymer. The mass transport limiting membrane may comprise at least a crosslinked polyvinylpyridine homopolymer or copolymer. The analyte sensors may determine a lactate concentration in a biological fluid, particularly in vivo, which may be correlated to various physiological conditions.