SPR Tear Osmolarity Sensor Nanoliter Sample Analysis

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Solution Overview

Problem

Current diagnostic methods for dry eye syndrome are inadequate, particularly in clinical settings, due to the limitations of existing osmometers that are not suited for nanoliter tear samples and lack of a 'gold standard' for diagnosis and treatment monitoring.

Innovation Solution

A Surface Plasmon Resonance (SPR) based device that measures osmolarity and protein concentration in nanoliter tear samples using a sensing platform with immobilized antibodies, allowing for accurate and efficient detection of dry eye syndrome.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional osmometers are used to measure tear samples, then measurement capability is provided, but they cannot handle nanoliter sample volumes which are typical for tear samples

Engineering Contradiction:
Improvesample volumeVSAvoidmeasurement reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The invention changes the measurement parameter from bulk solution measurement to surface-based measurement. The SPR sensor detects osmolarity by measuring changes in refractive index at the sensor surface, allowing nanoliter volumes to be measured effectively. This parameter change enables reliable measurement of the extremely small tear sample volumes that conventional osmometers cannot handle.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional osmometers are used, then osmolarity measurement is possible, but the devices are cumbersome and not suitable for clinical environments

Engineering Contradiction:
Improvedevice portabilityVSAvoidosmolarity measurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The invention replaces the mechanical and thermal measurement systems of conventional osmometers with an optical SPR-based system. This substitution eliminates the need for large sample chambers, heating elements, and mechanical sample handling mechanisms, resulting in a compact, portable device that maintains measurement precision while being suitable for clinical environments.

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

3Adaptability or versatility

If existing diagnostic methods are used for dry eye syndrome, then diagnosis can be performed, but there is no gold standard test that both diagnoses dry eye and monitors treatment effect

Engineering Contradiction:
Improvediagnostic versatilityVSAvoiddiagnosis reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention creates a universal diagnostic platform that can perform multiple functions: initial dry eye diagnosis through osmolarity measurement, treatment effect monitoring through repeated measurements, and differentiation of dry eye subtypes. The SPR-based osmometer serves as both a diagnostic and monitoring tool, fulfilling the need for a gold standard test that addresses both aspects.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 SPR device provides a simple, cost-effective, and accurate means to diagnose dry eye syndrome, enabling timely detection and differentiation between various dry eye conditions, overcoming the limitations of conventional osmometers and facilitating early intervention.

Implementation Method 1

The apparatus of claim 1 wherein the sensing surface comprises a thin film of metal disposed over an optically transparent substrate

Methodology Applied
Scientific EffectSurface Plasmon Resonance: Resonance

Implementation Method 2

operating the surface plasmon resonance apparatus to determine one or more solute or analyte concentrations of the tear sample

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2188615B1Device for measuring concentrations of constituents of tear sample
Publication Date: 2018.02.14 LACRISCIENCES LLC
  • EP2188615B1 patent drawingFigure 1
  • EP2188615B1 patent drawingFigure 2A~2C
  • EP2188615B1 patent drawingFigure 3A~3B

AI summary

A medical diagnostic method utilizes a surface plasmon resonance apparatus provided with a sensing surface. A tear sample from an eye of a patient is placed into contact with the sensing surface. The surface plasmon resonance apparatus is then operated to determine concentrations of solutes such as salt and antigenic analytes in the tear sample.