Closed-Loop Electrochemical pH Modulation for Ionic Strength Sensing

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Solution Overview

Problem

Current methods for monitoring chemical reactions face challenges in maintaining a constant pH environment, which can compromise enzyme efficiency and require deconvolution to quantify DNA concentration during processes like PCR, and are not effectively captured by optical systems.

Innovation Solution

A closed-loop device with a pH modulating agent, electronic controller, working electrode, counter electrode, and sensing element is used to maintain a constant pH in the bulk solution by detecting changes in ionic strength through localized pH modulation near the working electrode, allowing for sensitive monitoring of chemical reactions without disturbing pH-sensitive components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If diluted buffer solution is used to increase measurement sensitivity, then pH change detection sensitivity is improved, but enzyme efficiency is compromised

Engineering Contradiction:
ImprovepH change detection sensitivityVSAvoidenzyme efficiency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent divides the solution into two functional zones: a bulk buffer region that maintains constant pH for enzyme stability, and a localized measurement zone near the electrode where pH changes are detected. This segmentation allows the bulk buffer to preserve enzyme efficiency while the measurement zone provides sensitive pH detection through electrochemical means.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an electrochemical sensing system as an intermediary between the buffer solution and the measurement process. Instead of directly measuring pH changes in the bulk solution, the system uses electrode-based detection to sense ion concentration changes, thereby maintaining buffer integrity while achieving sensitive detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If direct pH measurement is used to monitor reaction progress, then reaction monitoring capability is improved, but deconvolution is required to separate pH effects from DNA quantification

Engineering Contradiction:
Improvereaction monitoring capabilityVSAvoiddeconvolution requirement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces direct optical pH measurement with electrochemical sensing. By using electrodes to detect ion concentration changes through electrochemical signals, the system achieves reaction monitoring without the need for optical pH measurement and subsequent deconvolution processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electrochemical sensing system serves as an intermediary that directly detects reaction progress through ion concentration changes, bypassing the need to measure pH and perform deconvolution calculations. This intermediary approach simplifies the measurement process while maintaining monitoring capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If constant pH environment is maintained to preserve enzyme functionality, then enzyme efficiency is improved, but sensitivity to detect early-stage ion concentration changes is reduced

Engineering Contradiction:
Improveenzyme efficiencyVSAvoidion concentration change detection sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent creates distinct functional zones: a bulk buffer region that maintains constant pH to preserve enzyme efficiency, and a localized electrochemical sensing zone that detects ion concentration changes. This segmentation allows simultaneous achievement of both constant pH environment and sensitive detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrochemical sensing system acts as an intermediary that can detect ion concentration changes in the bulk buffer without disrupting the constant pH environment. The electrode-based detection method provides sensitivity for early-stage reaction monitoring while the buffer maintains enzyme functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 high-sensitivity monitoring of chemical reactions at an early stage with constant pH, maintaining enzyme functionality and providing faster detection and improved stability for biosensors and bioreactors, while avoiding the need for deconvolution and capturing ion concentration changes before measurable pH shifts.

Implementation Method 1

applying a current or voltage to the working electrode, whereupon the pH modulating agent causes a change of a pH value in a zone adjacent to the surface of the working electrode

Methodology Applied
Scientific EffectElectrochemical pH modulation: Electrolysis

Implementation Method 2

detecting the change of ionic strength of the buffered solution with the closed-loop device

Methodology Applied
Scientific EffectIonic strength detection: Conduction (electrical)

Data Source

PatentEP4050111B1Measuring ion strength using closed-loop electrochemical ph modulation
Publication Date: 2023.11.08 ROBERT BOSCH GMBH
  • EP4050111B1 patent drawingFigure 1
  • EP4050111B1 patent drawingFigure 2
  • EP4050111B1 patent drawingFigure 3

AI summary

Provided is a method for monitoring a change of ion strength in a sample solution by a closed-loop device that provides continuous cycling of electrochemical pH modulation between predefined pH values. In particular, the change of ion strength may be induced by a chemical reaction and may ultimately alter the electrical control parameters of the closed-loop device. By measuring such electrical control parameters, the degree and progress of the underlying chemical reaction may be monitored.