Lactate Oxidase Variants for Wide-Range Sweat Lactate Detection
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Solution Overview
Problem
Current biosensors for lactate detection are invasive, require large fluid volumes, and struggle with accuracy due to pH and salinity differences between blood and sweat, limiting their effectiveness in non-invasive lactate level monitoring.
Innovation Solution
Development of lactate oxidase variants with reduced affinity to lactate, featuring specific amino acid substitutions (A95N, A95Q, A96C, S175C, and carboxymethylated S175C) that generate a detectable current in response to lactate concentration, allowing for non-invasive detection in various liquid samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional biosensors use wild-type lactate oxidase, then they achieve high affinity to lactate, but the detectable range is limited and accuracy deteriorates in samples with varying pH and salinity
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of lactate oxidase at specific positions (95, 96, and/or 175) to alter the enzyme's physical-chemical properties. These mutations change the enzyme's affinity characteristics and operational parameters, enabling it to function accurately across a broader pH range (4-9) and salinity conditions, thereby resolving the contradiction between detection precision and adaptability
2Measurement precision
If biosensors are designed for blood lactate detection, then they achieve accurate measurement in blood, but they cannot be used for non-invasive detection in sweat and other body fluids
Solution Approach 1:
The patent achieves universality by engineering lactate oxidase variants that can accurately detect lactate across multiple body fluids including blood, sweat, saliva, and interstitial fluid. The modified enzyme maintains measurement precision in blood while gaining the capability to function in sweat and other fluids with different pH and compositional characteristics, making the biosensor universally applicable for both invasive and non-invasive monitoring
3Reliability
If biosensors require large fluid volumes for operation, then they achieve sufficient signal for detection, but they become invasive and less user-friendly
Solution Approach 1:
The patent applies parameter changes by modifying the enzyme's kinetic and affinity parameters through amino acid mutations. These changes optimize the enzyme's catalytic efficiency and signal generation characteristics, enabling reliable detection with smaller fluid volumes. This resolves the contradiction by maintaining detection reliability while reducing the invasive sample collection requirements
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 lactate oxidase variants enable accurate lactate detection in a wide range, from 0 to 300 mM, in diverse liquid samples with varying pH and salinity, overcoming the limitations of conventional biosensors.
Implementation Method 1
lactate oxidase variants...give rise to a wider detectable range
Implementation Method 2
measuring a current generated by the reaction between the lactate oxidase variant and the lactate
Data Source
AI summary
Disclosed herein is directed to a lactate oxidase variant that exhibits reduced affinity to lactate as compared to a wild-type lactate oxidase. The lactate oxidase variant has one or more amino acid substitutions occurring at positions 95, 96, and/or 175 of the wild-type amino acid sequence. Also disclosed herein is a method for detecting and quantifying lactate in various liquid samples by using the present lactate oxidase variant. The method mainly includes steps of contacting the liquid sample with said lactate oxidase variant; measuring a current generated by the reaction between the lactate oxidase variant and the lactate in the liquid sample; and determining the concentration of lactate in the liquid sample by interpolating or extrapolating the current with that of a control sample having a known concentration of lactate.