ESR Determination in Electrochemical Biosensors

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Solution Overview

Problem

Existing electrochemical test strips face challenges in accurately measuring analyte concentrations due to voltage drops caused by equivalent series resistance (ESR), leading to unreliable measurement results, particularly when using thin conductive paths or materials with high resistance.

Innovation Solution

A method to determine equivalent series resistance (ESR) by generating an excitation voltage signal and analyzing the response signal flank to calculate ESR using the relation ESR = U measured * R ref / (U target - U measured), allowing for compensation of voltage drops and improving measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thin conductive paths or high-resistance materials are used in test strips, then manufacturing costs are reduced and device miniaturization is enabled, but voltage drops occur leading to measurement errors and reduced reliability

Engineering Contradiction:
Improvemanufacturing costVSAvoidmeasurement reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by measuring the equivalent series resistance (ESR) before the actual analyte measurement and using this pre-acquired information to compensate for voltage drops during the measurement process. The method performs an ESR measurement step prior to the analyte detection, storing the ESR value for subsequent compensation calculations, thereby eliminating the harmful voltage drop effects without requiring thicker conductive paths

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by dynamically adjusting the excitation voltage based on the measured ESR value. The system modifies the excitation voltage parameter to compensate for the voltage drop caused by high ESR, ensuring that the actual voltage applied to the electrochemical cell remains accurate despite variations in conductive path resistance or material properties

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If thin conductive paths are used, then device size is reduced, but equivalent series resistance increases causing voltage drops and measurement inaccuracies

Engineering Contradiction:
Improvedevice sizeVSAvoidmeasurement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent measures the ESR parameter in advance before performing the actual analyte concentration measurement. This preliminary ESR characterization enables the system to compensate for voltage drops during the measurement process, maintaining measurement accuracy despite the use of thin conductive paths that reduce device size

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the measured ESR value to adjust the excitation voltage or correction factors applied during analyte measurement. The system continuously monitors and compensates for the effects of high ESR, creating a closed-loop control that maintains measurement precision in miniaturized devices with thin conductive paths

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If materials with high resistance are used, then manufacturing cost is reduced, but voltage drops occur leading to unreliable measurement results

Engineering Contradiction:
Improvematerial costVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent performs preliminary ESR measurement to characterize the resistance properties of the conductive materials used in the test strip. By acquiring this resistance information before the actual measurement, the system can apply appropriate compensation to maintain measurement accuracy despite using high-resistance, low-cost materials

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent adjusts measurement parameters based on the measured ESR value, modifying the excitation voltage or calculation corrections to account for the high resistance of the conductive materials. This dynamic parameter adjustment ensures accurate analyte measurement even when using cost-effective high-resistance materials

Inventive Principle:
Principle #35Parameter changes

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 method enables faster and more reliable determination of analyte concentrations by accurately accounting for ESR, reducing measurement errors and enhancing the precision of electrochemical biosensors.

Implementation Method 1

applying a first excitation voltage signal to at least two measurement electrodes; measuring a response signal

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

determining an ohmic signal portion from a shape and a height of the signal flank; determining at least one information on an equivalent series resistance from the ohmic signal portion according to the relation ESR = U measured * R ref / (U target - U measured)

Methodology Applied
Scientific EffectOhm's law: Ohm's Law

Data Source

PatentEP3724648B1Method and device for determining an information on an equivalent series resistance
Publication Date: 2026.03.11 F HOFFMANN LA ROCHE & CO AG
  • EP3724648B1 patent drawingFigure 1A~1B
  • EP3724648B1 patent drawingFigure 1C~1D
  • EP3724648B1 patent drawingFigure 2A~2B

AI summary

A method for determining an information on an equivalent series resistance is disclosed. The method comprises the following steps: - generating at least one excitation voltage signal and applying the excitation voltage to at least two measurement electrodes (116); - measuring a response signal; - determining a signal flank from the response signal and determining an ohmic signal portion from one or both of shape and height of the signal flank; - determining the information on the equivalent series resistance from the ohmic signal portion.