Screen-Printed Ion-Selective Sensors for Objective Tear Osmolarity

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Solution Overview

Problem

Current diagnostic methods for Dry Eye Disease (DED) such as tear breakup time and tear osmolarity are limited by subjective interpretation and result variability, failing to provide a comprehensive assessment of tear film composition.

Innovation Solution

Development of a screen-printed, solid contact ion-sensitive electrode (SP-SC-ISE) with a conducting layer and ion-sensing membrane, utilizing conductive polymers and nanoparticles, capable of measuring osmolarity through ion-transfer stripping voltammetry, providing a disposable and paper-based electrochemical sensor for tear analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If current diagnostic methods (tear breakup time, Schirmer test, tear osmolarity) are used, then diagnosis can be performed, but the results suffer from subjective interpretation and variability

Engineering Contradiction:

Improvediagnostic accuracyVSAvoidmethod simplicity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical/manual diagnostic methods (tear breakup time observation, Schirmer test paper) with an electrochemical sensing system that uses ion-selective electrodes and conductive polymers to automatically detect tear film composition, eliminating subjective interpretation and improving measurement precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the measurement parameter from subjective visual assessment to objective electrochemical signals by using ion-selective electrodes that detect specific ions (Na+, K+, Ca2+) in tears, providing quantifiable and reproducible diagnostic data

Inventive Principle:

Principle #35Parameter changes

2Loss of information

If traditional tear osmolarity measurement is used, then osmolarity can be assessed, but the assessment is incomplete regarding tear film composition

Engineering Contradiction:

Improvecompleteness of tear film assessmentVSAvoidsensor structure

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent segments the tear film assessment into multiple independent ion measurements (Na+, K+, Ca2+) using separate ion-selective electrodes, each targeting a specific ion type, thereby providing comprehensive compositional information that goes beyond single-parameter osmolarity measurement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sensor system performs multiple diagnostic functions simultaneously by integrating several ion-selective electrodes that can detect different ions in the same tear sample, making the device universal for comprehensive tear film composition analysis rather than limited to single-parameter measurement

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If screen-printed electrodes with conductive polymers are used, then measurement precision is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrode coating uniformityVSAvoidfabrication process

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the physical state of conductive polymers from bulk material to nanoscale particles or molecules dispersed in a matrix, which allows for more uniform distribution and coating during screen printing, thereby improving manufacturing precision while maintaining ease of fabrication

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite materials combining conductive polymers with other materials (such as nanoparticles or porous matrices) to create screen-printable inks that maintain electrochemical activity while enabling precise and reproducible manufacturing through standard screen printing techniques

Inventive Principle:

Principle #40Composite materials

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 sensor offers accurate, objective measurement of osmolarity with high sensitivity and low cross-sensitivity to contaminants, enabling reliable diagnosis of DED with improved precision and ease of use.

Implementation Method 1

utilizing conductive polymers and nanoparticles, capable of measuring osmolarity through ion-transfer stripping voltammetry

Methodology Applied

Scientific EffectIon-transfer stripping voltammetry: Electrolysis

Implementation Method 2

the conducting layer comprises one or more conductive polymers, nanoparticles, or composite thereof

Methodology Applied

Scientific EffectConductive polymer conduction: Conduction (electrical)

Implementation Method 3

the ionophore comprises a Na+ ionophore

Methodology Applied

Scientific EffectIonophore binding: Adsorption

Data Source

PatentUS20250241560A1Compositions and methods for measuring osmolarity

Publication Date: 2025.07.31 ARKANSAS STATE UNIV

AI summary

The present invention is directed to an electrochemical sensor for the measurement of osmolarity.