Droplet Sorting via Multi-Wavelength Optical Co-Localization

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Solution Overview

Problem

Existing methods for analyzing and selecting microfluidic droplets are complex and expensive, particularly when distinguishing between droplets containing aggregated biological entities and those with single entities, leading to potential false positives or false negatives.

Innovation Solution

A method involving the measurement of at least two optical signals for each droplet to calculate parameters such as co-localization, droplet width, and peak coordinates, allowing for precise sorting based on these parameters to enhance fidelity in droplet selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual or automatic sorting machines are used to separate droplets, then droplet sorting can be performed, but the system becomes complex and expensive

Engineering Contradiction:
Improvedroplet sorting capabilityVSAvoidsorting system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical sorting machines with a digital image processing system. The method uses optical signals captured by a camera and processes them through image analysis algorithms to identify and sort droplets based on their visual characteristics, thereby eliminating the need for expensive automatic sorting machines while maintaining sorting functionality.

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

Solution Approach 2:

The patent creates an optical copy (image) of the droplets and performs analysis on this copy rather than directly manipulating the physical droplets with complex machinery. By capturing images and analyzing them digitally, the system achieves sorting capability without requiring complex mechanical intervention devices.

Inventive Principle:
Principle #26Copying

2Measurement precision

If fluorescent markers are used to identify reacted droplets, then droplet selection accuracy improves, but measurement precision requirements increase

Engineering Contradiction:
Improvedroplet identification accuracyVSAvoidoptical signal analysis complexity
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent utilizes fluorescent markers that emit light at specific wavelengths when excited, creating distinct color signals for different droplet states. The image processing system detects these color variations to identify reacted versus unreacted droplets, transforming the measurement task into a color-based optical detection problem that can be solved with standard imaging equipment.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent captures images with higher resolution and multiple wavelength channels than the minimum required, then processes only the relevant portions of the data. By acquiring excessive optical information (multiple wavelength channels, high spatial resolution) and selectively analyzing it, the system achieves high measurement precision while managing the complexity of signal analysis through focused processing of key parameters.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If droplets are sorted based on simple fluorescence intensity, then sorting speed increases, but measurement precision decreases leading to false positives or negatives

Engineering Contradiction:
Improvesorting throughputVSAvoiddroplet classification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent transitions from analyzing a single dimension (fluorescence intensity) to analyzing multiple dimensions simultaneously. The image processing system evaluates spatial distribution patterns, intensity values, and wavelength channel information together, creating a multi-dimensional characterization of each droplet. This allows accurate classification while maintaining high throughput, as the system can process multiple parameters in parallel from a single image capture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent performs preliminary image capture and analysis before the actual sorting decision is made. By pre-processing the optical signals and identifying droplet characteristics in advance, the system can make rapid sorting decisions based on pre-computed parameters, thereby maintaining high productivity while ensuring accurate classification through thorough preliminary analysis.

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

This approach enables more accurate and efficient selection of specific droplets by analyzing light intensity spatial distributions, improving the fidelity of droplet analysis and sorting processes.

Implementation Method 1

measuring for a droplet in a succession of droplets, at least two optical signals, each optical signal being representative of a light intensity spatial distribution in the droplet for an associated wavelength channel

Methodology Applied
Scientific EffectOptical detection: Absorption (EM radiation)

Data Source

PatentEP4219009A1Method for analyzing and selecting a specific droplet among a plurality of droplets and associated apparatus
Publication Date: 2023.08.02 HIFIBIO PARIS
  • EP4219009A1 patent drawingFigure 1
  • EP4219009A1 patent drawingFigure 2
  • EP4219009A1 patent drawingFigure 3~4

AI summary

The present invention relates to a method for analyzing and selecting a specific droplet among a plurality of droplets (4), comprising the following steps: - providing a plurality of droplets (4), - for a droplet (4) among the plurality of droplets, measuring at least two optical signals, each optical signal being representative of a light intensity spatial distribution in the droplet for an associated wavelength channel, - calculating a plurality of parameters from the optical signals, - determining a sorting class for a droplet according to calculated parameters, - sorting said droplet according to its sorting class, wherein the plurality of parameters comprises the coordinates of a maximum for each optical signal and a co-localization parameter and the at least two calculated parameters used for the determining step comprises the co-localization parameter.