Microfluidic Microparticle Sorting via Laser Viscosity Control

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Solution Overview

Problem

Current methods for sorting microparticles in fluid flows, such as those used in medical diagnostics, are inefficient, leading to delayed antibiotic therapy and high mortality rates due to the time-consuming process of pathogen identification and antibiotic sensitivity testing.

Innovation Solution

A microfluidic device with a fluidic branch that uses electromagnetic radiation to locally reduce the viscosity of the fluid at specific points, allowing for the efficient sorting of microparticles by altering the flow resistance and guiding them into desired outlet channels based on detection signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional electrocaloric fluid switching with resistance heaters is used, then thermal contact between heater and fluid is achieved, but the switching frequency is limited to 5 Hz due to wall heat capacity and indirect heating

Engineering Contradiction:
Improveswitching frequencyVSAvoidthermal insulation zones and high thermal conductivity materials
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/thermal contact-based resistance heater system with an optical heating system using laser radiation. This substitution eliminates the need for thermal contact through walls, removes the requirement for high thermal conductivity materials and thermal insulation zones, and enables much higher switching frequencies by directly heating the fluid at the switching point without wall heat capacity limitations.

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

2Speed

If laser radiation is used to heat buffer solution in flow cytometry, then viscosity changes enable particle sorting, but effective heating requires narrowing the exit to match laser beam diameter

Engineering Contradiction:
Improveheating efficiencyVSAvoidchannel geometry modification
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a localized heating zone at the switching point using laser radiation. Instead of modifying the entire channel geometry or heating large volumes of fluid, the laser beam is focused to heat only the specific region where viscosity reduction is needed, enabling precise control of fluid flow division without structural modifications to the channel.

Inventive Principle:
Principle #3Local quality

3Loss of time

If rapid pathogen identification and sorting is implemented, then specific antibiotic therapy can be initiated timely, but current methods require 24-48 hours for culture and sensitivity testing

Engineering Contradiction:
Improvediagnosis timeVSAvoidpathogen multiplication efficiency
Core Design Contradiction:
Loss of timeVSProductivity

Solution Approach 1:

The patent performs preliminary identification and sorting of pathogens directly from the blood sample before culture multiplication. By using optical detection and laser-induced viscosity changes to sort particles based on their scattering properties, the system identifies pathogens in real-time without waiting for 24-48 hour culture periods, enabling immediate initiation of specific antibiotic therapy.

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 rapid and effective sorting and characterization of microparticles, allowing for timely specific antibiotic therapy and quick initiation of countermeasures in medical and environmental applications, reducing the risk of harmful pathogen spread.

Implementation Method 1

comprises a switching unit for switching the branch as a function of the identification signal by temporarily introducing heat locally at at least one switching point of the branch to temporarily reduce the viscosity of the fluid at the switching point

Methodology Applied
Scientific EffectViscosity reduction through heating: Heating

Data Source

PatentEP3218107B1Method and device for sorting microparticles in a fluid flow
Publication Date: 2018.09.26 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3218107B1 patent drawingFigure 1
  • EP3218107B1 patent drawingFigure 2
  • EP3218107B1 patent drawingFigure 3

AI summary

The invention relates to a method and a device for sorting microparticles (6) in a fluid flow (5) whereby a microparticle (6) is detected by means of a detection unit and an identification signal is generated when the microparticle (6) passes a detection area (7), and at a switching point (8, 9), which is selected depending on the identification signal, of a branching with at least one inlet (2) and at least two outlets (3, 4), the viscosity of the fluid (5) is decreased by means of irradiation with electromagnetic radiation for a predetermined period of time once a predetermined time span after the generation of the identification signal has elapsed such that the proportion of the portions of the fluid flow (5) passing through the at least two outlets (3, 4) is changed in such a way that the microparticle (6) is guided through the outlet determined by the identification signal.