Hematocrit Electrode with Conductive Polymer for Glucose Correction
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Solution Overview
Problem
Existing biosensors for blood glucose monitoring face challenges due to the influence of hematocrit values, leading to inaccurate glucose measurements, with methods like alternating voltage increasing power consumption and complex sensor structures, and separation membranes being unstable due to sample viscosity.
Innovation Solution
A biosensor system with a hematocrit electrode coated with a water-soluble electrically conductive polymer, such as polyaniline, and a method involving specific voltage applications to measure and correct glucose concentrations based on hematocrit values, using a working electrode, counter electrode, and reference electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alternating voltage is applied to measure hematocrit value, then hematocrit measurement is achieved, but electric power consumption increases
Solution Approach 1:
The patent applies periodic alternating voltage at specific frequencies (50-1000 Hz, preferably 100-500 Hz) to the electrode to measure hematocrit value. This periodic action enables hematocrit measurement through impedance changes caused by red blood cells, while the frequency selection optimizes the balance between measurement accuracy and power consumption by avoiding resonance frequencies that would require excessive energy.
2Measurement precision
If separation membrane is used to separate blood plasma from whole blood, then glucose measurement accuracy is improved, but sensor structure becomes complex
Solution Approach 1:
The patent extracts and measures the hematocrit value (representing the blood cell component) separately from the glucose measurement. By measuring the impedance of the whole blood sample to determine hematocrit, and then using this information to correct the glucose reading, the method effectively separates the interfering blood cell component from the plasma glucose measurement without requiring physical separation membranes.
3Measurement precision
If separation membrane is used to separate blood plasma from whole blood, then glucose measurement is improved, but separation ability becomes unstable due to sample viscosity
Solution Approach 1:
The patent replaces the mechanical separation membrane system with an electrical measurement system. Instead of using a physical membrane to separate plasma from blood cells (which is affected by viscosity), the patent uses electrical impedance measurements at different frequencies to distinguish and measure the hematocrit component, then corrects the glucose reading accordingly. This substitution eliminates the reliability issues associated with membrane-based separation.
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
Enables accurate and efficient measurement of hematocrit values and glucose concentrations by correcting for hematocrit influences, reducing noise and power consumption while maintaining sensor simplicity.
Implementation Method 1
measuring the value of a second current which flows when a voltage of 400 to 800 mV is applied to the hematocrit electrode
Implementation Method 2
measuring the value of a first current which flows when a voltage of 0 to 400 mV is applied to the working electrode
Implementation Method 3
an electrically conductive polymer immobilized on the surface of the hematocrit electrode
Data Source
AI summary
Provided is a method for measuring the concentration of a substance in a blood sample, comprising: supplying the blood sample to a biosensor comprising a hematocrit electrode for measuring a hematocrit value on the surface of which electrode an electrically conductive polymer is covalently immobilized; and calculating the concentration of the substance from the measured value of a first current resulting from application of a first voltage; and correcting the concentration of the substance with the value of a second current resulting from application of a second voltage or the hematocrit value calculated from the value of the second current.