Inner Ear Cell Imaging via Two-Photon Fluorescence

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Solution Overview

Problem

Current imaging techniques are inadequate for visualizing inner ear cells due to the challenging access provided by the hard bone surrounding them, limiting diagnosis and treatment options for sensorineural hearing loss.

Innovation Solution

The method involves directing illumination radiation through a layer of bone or cartilage to induce nonlinear responses such as two-photon fluorescence and harmonic generation in inner ear cells, allowing for high-resolution imaging without the need for staining, using systems that include radiation sources, spatial light modulators, and endoscopes to adjust radiation distribution and detect emitted signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional imaging techniques (CT scanning, MRI) are used to image inner ear cells, then the imaging can be performed non-invasively, but the resolution is insufficient to establish diagnosis

Engineering Contradiction:
Improveimaging resolutionVSAvoidinvasiveness
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the parameter of light wavelength to infrared range (e.g., 800-1000 nm) to enable deeper penetration through bone tissue while maintaining high resolution imaging capability through two-photon excitation microscopy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical biopsy procedures with optical imaging methods that use infrared light to penetrate bone and image cells non-invasively, eliminating the need for surgical intervention

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

2Measurement precision

If staining is applied to inner ear cells to enhance imaging contrast, then the imaging quality improves, but cell death occurs

Engineering Contradiction:
Improveimaging contrastVSAvoidcell viability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent exploits the natural autofluorescence properties of cellular components (NADH, FAD, collagen) to generate imaging contrast without external staining agents, allowing cells to serve themselves for contrast generation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses two-photon excitation with infrared light to stimulate autofluorescence from endogenous chromophores, changing the excitation mechanism to avoid toxic staining while maintaining contrast

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the bone layer surrounding inner ear cells is removed to access cells for imaging, then direct cell access is achieved, but hearing function is destroyed

Engineering Contradiction:
Improvecell accessibilityVSAvoidhearing function
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses infrared light as an intermediary that can penetrate through the bone layer to reach inner ear cells without physical contact or removal of bone, enabling imaging through the natural barrier

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical access methods (drilling, removing bone) with optical penetration using infrared light, substituting physical intervention with electromagnetic wave transmission

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

4Length of stationary object

If standard imaging wavelengths are used to image through bone, then the imaging setup is simple, but the penetration depth is insufficient

Engineering Contradiction:
Improvepenetration depthVSAvoidimaging system complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent changes the wavelength parameter to infrared range (800-1000 nm) where bone tissue has higher transmission properties, enabling deeper penetration while using standard two-photon microscopy equipment

Inventive Principle:
Principle #35Parameter changes

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 approach enables non-invasive, high-resolution imaging and identification of inner ear cells, including damaged ones, by analyzing emission spectra, facilitating better diagnosis and potential treatments for hearing-related issues.

Implementation Method 1

The wavelength of the radiation, and in some embodiments, the temporal and/or spatial distributions of the radiation, are selected to induce nonlinear responses in the cells that are illuminated. Examples of nonlinear responses that can be generated using the methods and systems disclosed herein include two-photon fluorescence (TPF) emission

Methodology Applied
Scientific EffectTwo-photon fluorescence: Fluorescence

Implementation Method 2

Examples of nonlinear responses that can be generated using the methods and systems disclosed herein include two-photon fluorescence (TPF) emission and harmonic generation (HG), e.g., second harmonic generation (SHG)

Methodology Applied
Scientific EffectSecond harmonic generation: Second Harmonic Generation

Implementation Method 3

In some implementations of these methods, the system is configured to focus on autofluorescence due to flavin adenine dinucleotide (FAD)

Methodology Applied
Scientific EffectAutofluorescence: Fluorescence

Data Source

PatentEP2770899B1Tissue and cellular imaging
Publication Date: 2021.03.10 MASSACHUSETTS EYE & EAR INFARY
  • EP2770899B1 patent drawingFigure 1~3
  • EP2770899B1 patent drawingFigure 4A~5
  • EP2770899B1 patent drawingFigure 6A~7

AI summary

Systems and methods for imaging ear tissue include: directing illumination radiation to pass through an intact biological structure and be incident on ear tissue that does not include an exogenous fluorophore, at a plurality of locations, the illumination radiation including a plurality of light pulses each having a temporal duration of 500 femtoseconds or less; for each one of the plurality of locations, using a detector to detect radiation emitted from the location that passes through the intact biological structure; and forming an image of the tissue based on the detected radiation at each of the plurality of locations, where the emitted radiation corresponds to endogenous two-photon fluorescence of the tissue.