Fiber-Optic Interferometric Sensor for Label-Free Analyte Detection

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Solution Overview

Problem

Current diagnostic methods for detecting analytes in samples often require labeled molecules, are costly, and lack flexibility in detecting different types of analytes using the same device, while also being prone to toxicity and limited in monitoring small sample volumes.

Innovation Solution

A disposable fiber optic detector tip apparatus with a light source, detector unit, and optical coupling assembly that uses interferometry to detect analyte binding without labels, allowing for real-time monitoring of binding reactions in small volumes and enabling the use of visible wavelength light sources, facilitating multiplexed analyses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If labeled molecules are used for analyte detection, then detection sensitivity is improved, but cost increases and toxicity risks arise

Engineering Contradiction:
Improvedetection sensitivityVSAvoidtoxicity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the labeling step from the traditional detection workflow. By using fiber-optic interferometry that detects refractive index changes directly at the sensor surface, the method removes the need for fluorescent, radioactive, or enzymatic labels, thereby eliminating associated toxicity and cost issues while maintaining detection sensitivity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the chemical/biological labeling mechanism with a physical optical measurement mechanism. Instead of using labeled molecules that require chemical attachment and produce harmful byproducts, the system uses light interference patterns to detect analyte binding events, substituting a harmful chemical approach with a benign physical approach

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

2Measurement precision

If solid-phase assays with immobilized anti-analyte molecules are used, then specific binding detection is improved, but device flexibility and adaptability decrease

Engineering Contradiction:
Improvebinding detection accuracyVSAvoiddevice flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The fiber-optic sensor platform provides universal detection capability that can detect multiple types of analytes (proteins, nucleic acids, small molecules, cells) using the same basic device. The sensor surface can be regenerated and re-used with different ligands, making the device adaptable to various applications without requiring dedicated hardware for each analyte type

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

Solution Approach 2:

The invention enables easy changes in detection parameters by modifying the sensor surface chemistry or immobilized ligands rather than changing the entire device. The fiber-optic sensor can be functionalized with different anti-analyte molecules for different targets, allowing rapid adaptation to new analytes while maintaining the same detection platform

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If traditional optical detection methods are used, then detection capability is achieved, but real-time monitoring of small sample volumes is limited

Engineering Contradiction:
Improvedetection capabilityVSAvoidsample volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The fiber-optic sensor uses a thin film sensing layer at the fiber tip that creates an evanescent field extending into the sample. This configuration allows detection in extremely small sample volumes (microliters or nanoliters) because the evanescent field interacts only with molecules in the immediate vicinity of the fiber surface, maximizing detection efficiency in limited volumes

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The fiber-optic sensor enables real-time, label-free detection that continuously monitors binding events as they occur without requiring additional reagents or complex sample preparation. The system provides ongoing measurement of analyte concentration and binding kinetics in the same small sample volume throughout the experiment

Inventive Principle:
Principle #25Self-service

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 real-time monitoring of analyte binding reactions without labels, reducing costs and potential toxicity, and allowing for flexible detection of various analytes in small sample volumes, including in vivo spaces, with improved sensitivity and accuracy.

Implementation Method 1

A detector in the apparatus operates to detect a change in the thickness of the first reflecting layer resulting from binding of analyte to the analyte-binding molecules, when the assembly is placed in the solution of analyte, by detecting a shift in phase of light waves reflected from the first and second surfaces

Methodology Applied
Scientific EffectPhase shift interferometry: Interference

Implementation Method 2

Light from the source is directed to and reflected from the two reflecting surfaces. The interfering reflected beams are directed to the detector unit

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP1891395B1Fiber-optic assay apparatus based on phase-shift interferometry
Publication Date: 2015.09.16 PALL FORTEBIO
  • EP1891395B1 patent drawingFigure 1~2
  • EP1891395B1 patent drawingFigure 3A~3B
  • EP1891395B1 patent drawingFigure 4A

AI summary

Apparatus and method for detecting an analyte in a sample based on optical interference. The apparatus includes a light source, detector unit and one or more disposable detector tips. The apparatus also includes an optical coupling assembly that couples light from the source to the detector tips, and from the detector tips to the detector unit.