Evanescent Field Optical Detection for Automated Diagnostic Testing

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Solution Overview

Problem

Human observation is unreliable for determining diagnostic test results in binding assays, necessitating the development of automated or electronic test evaluation systems that are efficient and cost-effective for various test situations.

Innovation Solution

A compact diagnostic test system that detects target species by utilizing a light guide with an evanescent field to emit light transversely, integrated with a detector and light source, allowing for efficient and cost-effective detection of test results through optical integrated circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If human observation is used to determine test results, then the system remains simple and low cost, but the reliability and accuracy of test results deteriorate

Engineering Contradiction:

Improvetest result reliabilityVSAvoidtest system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/visual observation system with an optical detection system. A light source illuminates the indicator region, and a detector (photodetector, photodiode, or camera) captures the emitted or reflected light signals. This substitution of mechanical observation with optical-electronic detection resolves the contradiction by providing automated, reliable result determination without requiring human judgment, while maintaining cost-effectiveness through the use of standard optical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If automated electronic test evaluation is implemented, then test result reliability improves, but device complexity and cost increase

Engineering Contradiction:

Improvetest result reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the optical detection components (light source, waveguide, detector) into an integrated test system that can be manufactured as a single unit. The binding agent is coated directly on the waveguide surface, and the detector is positioned to read the indicator region within the same housing. This integration approach reduces manufacturing complexity and cost compared to separate components, while maintaining automated electronic evaluation for reliable results.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a disposable test strip or test cassette containing the binding agent and indicator region, which is replaced after each use. The expensive automated detection components (light source, detector, processing electronics) are reused multiple times. This strategy reduces the overall system cost by concentrating investment in durable detection hardware while using inexpensive consumables, making automated testing economically viable.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If a compact integrated test system is created, then ease of use and accessibility improve, but manufacturing precision requirements worsen

Engineering Contradiction:

Improvetest system usabilityVSAvoidcomponent alignment precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent pre-positions the binding agent on the waveguide surface and pre-aligns the detector to read the indicator region during manufacturing. The test strip is pre-assembled with the binding agent coating in the correct location. This preliminary positioning eliminates the need for complex real-time alignment during use, making the system easy to operate while managing manufacturing precision requirements through upfront setup rather than during operation.

Inventive Principle:

Principle #10Preliminary action

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

Enables reliable and automated detection of target species with reduced human intervention, providing efficient and cost-effective results for a wide range of diagnostic tests.

Implementation Method 1

a light guide and a binding agent positioned to trap a target species or complex in an evanescent field of the light guide

Methodology Applied

Scientific EffectEvanescent field: Total Internal Reflection

Implementation Method 2

The target species or complex when present interacts with the evanescent field of light propagating through a waveguide and emits light in a direction transverse to the waveguide, for example, by fluorescence or scattering

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 3

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS8570518B2Methods and materials for detection of target species

Publication Date: 2013.10.29 ALVERIX INC

AI summary

A test system includes an optical medium, a binding agent capable of capturing a target complex, and a light detector. The optical medium provides a light path, and the binding agent is positioned to hold the target complex in an evanescent field created by propagation of light along the light path. The complex interacts with the evanescent field and emits light that the detector positioned to detect. The optical medium and the detector can be included in an optical integrated circuit where detected light passes through the optical medium transverse to the direction of the light path.