Sensor Chip Electrode Segmentation for Stable Hematocrit Measurement
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Solution Overview
Problem
Existing sensor chips for measuring hematocrit (Hct) values in blood samples suffer from insufficient detection sensitivity, particularly at low Hct value measuring voltages, leading to unstable measurements.
Innovation Solution
A sensor chip design where the oxidant of a redox substance is in contact with the counter electrode and the reductant is in contact with the working electrode, with the other form of the redox substance being substantially not in contact with either electrode, to stabilize the amplitude fluctuations of the redox current and enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electron mediator is disposed on both working and counter electrodes to measure Hct value, then the measurement can be performed, but the detection sensitivity is insufficient and the redox current amplitude fluctuates widely at low voltages
Solution Approach 1:
The patent divides the electrode system into two distinct functional parts: the working electrode is dedicated to analyte detection while the counter electrode is dedicated to Hct measurement. This segmentation allows each electrode to perform its specific function optimally without interference, resolving the contradiction between measurement sensitivity and stability.
Solution Approach 2:
The patent applies different reagent configurations to different electrodes: the working electrode contains analyte-specific enzymes and electron mediators for sensitive analyte detection, while the counter electrode contains redox substances specifically for stable Hct measurement. This local differentiation of qualities enables each electrode to excel at its designated measurement task.
2Measurement precision
If the voltage applied across working and counter electrodes is decreased to reduce interference, then the analyte measurement interference is reduced, but the redox current amplitude fluctuates over a wide range making stable Hct measurement impossible
Solution Approach 1:
By segmenting the electrode functions, the patent enables the counter electrode to generate sufficient redox current for stable Hct measurement even at low applied voltages, while the working electrode performs analyte detection without significant interference from the reduced voltage.
Solution Approach 2:
The patent uses separate electron mediators for each electrode function: one mediator system for the working electrode handles analyte detection, while another mediator system on the counter electrode handles Hct measurement. These intermediary substances enable the low-voltage operation to work for both measurements simultaneously.
3Ease of manufacture
If both reductant and oxidant of electron mediator are disposed on blood sample holder to dissolve by blood sample, then the redox reaction can occur, but the redox current amplitude changes only slightly with Hct value changes resulting in insufficient detection sensitivity
Solution Approach 1:
The patent segments the redox substance placement: the oxidant is disposed on the counter electrode while the reductant is disposed separately on the blood sample holder. This segmentation creates a more sensitive configuration where the redox current at the counter electrode responds more strongly to Hct value changes.
Solution Approach 2:
The patent uses the blood sample itself as an intermediary medium that contains the reductant, which reacts with the oxidant on the counter electrode. This intermediary approach enhances the sensitivity of Hct detection by utilizing components naturally present in the blood sample.
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
This configuration allows for stable and sensitive measurement of Hct values even at low measuring voltages, improving detection accuracy and reliability.
Implementation Method 1
the oxidant of a redox substance is in contact with the counter electrode and substantially not in contact with the working electrode, and a reductant of the redox substance in contact with the working electrode and substantially not in contact with the counter electrode
Data Source
AI summary
Voltage is applied across a counter electrode and a working electrode, with which a blood sample is in contact, in such a state that an oxidant in a redox substance is not substantially in contact with a working electrode but is in contact with a counter electrode and a reductant is not substantially in contact with the counter electrode but is in contact with the working electrode, whereby the reductant and the oxidant are respectively oxidized and reduced to measure current produced upon the oxidation and reduction. According to the above constitution, while lowering the voltage applied across the working electrode and the counter electrode, the Hct value of the blood sample can be measured stably with a satisfactory detection sensitivity. This measurement can be carried out with a sensor chip comprising a working electrode (11), a counter electrode (12), and a blood sample holding part (14) having branch parts (18a, 18b). A first reagent (13) consisting essentially of an oxidant in a redox substance is disposed in contact with the surface of a counter electrode which faces the branch part (18b), and a second reagent (19) consisting essentially of a reductant is disposed in contact with the surface of a working electrode that faces the branch part (18a).