Fluorescence Event Counting for Microscopy Quantification

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Solution Overview

Problem

Current high-resolution microscopy methods for recording and evaluating fluorescence events are computationally expensive and prone to errors due to noise and intensity fluctuations, limiting their ability to provide accurate, quantitative data, especially at high spatial resolutions.

Innovation Solution

A method that involves initializing counters for defined regions in a microscope image, identifying and counting non-overlapping fluorescence events without sub-pixel localization, and outputting the count as the number or concentration of fluorophores, allowing for rapid, quantitative evaluation by transforming a subset of fluorophores into an excitable state and imaging their diffraction-broadened fluorescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-resolution microscopy methods (PALM, STORM) are used to achieve high spatial resolution, then the resolving power is improved beyond the diffraction limit, but the computational cost and time required for image reconstruction become extremely expensive and time-consuming

Engineering Contradiction:
Improvespatial resolutionVSAvoidimage reconstruction time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential information needed for quantitative analysis - the number of fluorescence events in defined regions - while discarding the computationally intensive step of full high-resolution image reconstruction. By counting events directly from the raw microscope image without performing complex iterative reconstruction algorithms, the method achieves rapid quantitative evaluation while maintaining accuracy for concentration measurements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the image evaluation process into discrete, countable fluorescence events within specifically defined regions of interest. Instead of processing the entire image to generate a high-resolution reconstruction, the method divides the image into regions and independently counts fluorescence events in each region, significantly reducing computational requirements while providing quantitative data for each segment.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If traditional fluorescence microscopy is used to examine small volumes with high spatial resolution, then the spatial accuracy is improved, but the signal-to-noise ratio deteriorates due to increased Poisson variance and detector noise

Engineering Contradiction:
Improvespatial accuracyVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies partial action by transforming only a small subset of fluorophores into an excitable state rather than activating all fluorophores. This stochastic activation ensures that fluorescence events are sufficiently sparse to be resolved individually even in small volumes, thereby maintaining Poisson statistics with manageable variance and improving the signal-to-noise ratio while preserving spatial accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs preliminary transformation of fluorophores into an excitable state before imaging, controlling the density of excited fluorophores to ensure non-overlapping intensity distributions. This preliminary step allows individual event detection with high confidence, improving reliability by reducing noise from overlapping signals while maintaining the ability to resolve small volumes with high spatial accuracy.

Inventive Principle:
Principle #10Preliminary action

3Illumination intensity

If a large number of fluorophores are activated simultaneously to improve signal intensity, then the brightness is improved, but the ability to resolve individual events deteriorates due to overlapping intensity distributions

Engineering Contradiction:
Improvefluorescence intensityVSAvoidevent resolution
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent deliberately activates only a partial subset of fluorophores - specifically enough to provide adequate signal intensity but few enough to ensure non-overlapping intensity distributions. By controlling the transformation efficiency and density of excited fluorophores, the method achieves an optimal balance where individual events remain resolvable while maintaining sufficient brightness for reliable detection.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the parameter of fluorophore density in the excitable state by controlling the transformation process. By adjusting the fraction of fluorophores transformed into the excitable state, the method optimizes the balance between signal intensity and event resolution, ensuring that intensity distributions remain sufficiently separated for accurate counting while maintaining adequate brightness for detection.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If subjective visual evaluation by human observers is used to analyze high-resolution images, then flexibility in interpretation is improved, but measurement consistency and objectivity deteriorate due to subjective influences

Engineering Contradiction:
Improveinterpretation flexibilityVSAvoidevaluation consistency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical process of human visual evaluation with an automated computational method that counts fluorescence events based on objective criteria. By substituting human observation with algorithmic event detection and counting, the method eliminates subjective influences while maintaining the ability to evaluate fluorescence distributions, thereby improving measurement consistency and objectivity without sacrificing interpretational flexibility.

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

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 significantly improves the signal-to-noise ratio, reduces subjective influences, and enables high-dynamic-range imaging, allowing for accurate, quantitative determination of fluorophore concentrations and stoichiometry, even in regions with high fluorophore densities, thus overcoming limitations of existing methods like PALM.

Implementation Method 1

a small number of randomly distributed fluorescent dye molecules (fluorophores) are transformed (activated) into an excitable state by light of very low intensity at an activation wavelength

Methodology Applied
Scientific EffectPhoto-activation: Photochromism

Implementation Method 2

the sample is then at least partially irradiated with excitation light, with fluorescence radiation emitted by the sample being imaged diffraction-broadened by means of a microscope objective

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

fluorescence radiation emitted by the sample being imaged diffraction-broadened by means of a microscope objective

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP2446314B1Method for evaluating fluorescence results in a microscope image
Publication Date: 2019.10.23 CARL ZEISS MICROSCOPY GMBH
  • EP2446314B1 patent drawingFigure 1
  • EP2446314B1 patent drawingFigure 2
  • EP2446314B1 patent drawingFigure 3A~4

AI summary

Research fields such as system biology depend on quantitative data, which until now were possible to determine only with low accuracy by means of fluorescence microscopy. The invention is to enable a quantitative evaluation of microscopically recorded images having fewer errors and is to be useable in connection with high-resolution methods, in particular with high speed. A microscope image (2) is evaluated, in which the intensity distributions of the fluorescence events in each case have a diffraction-related expansion, which corresponds to an expansion of a dot transmission function of the microscope (1), and are arranged spatially without overlap or at least largely spatially without overlap, in that at least one counter per region (R, R1, R2) of the microscope image (2), which region is predetermined to be evaluated, is initialized, at least one fluorescence event in a region (R, R1, R2) of the microscope image (2), which region is to be evaluated, is identified, and the counter corresponding to the respective region (R, R1, R2) is incrementally increased with each fluorescence event identified in the region (R, R1, R2). By means of counting, the signal-to-noise ratio can be drastically improved at high evaluation speed.