Acoustic Cell Sorting via Droplet Intersection

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Solution Overview

Problem

High-speed cell sorting technologies face challenges in achieving high throughput and sterility due to mechanical complexity and cost limitations, particularly in clinical applications, where traditional droplet-based systems are not biosafe and microfluidic devices operate at lower rates and are costly.

Innovation Solution

A high-speed fluid switch system that uses a micro-flow device with a source channel, deflection channel, and waste channel, where a stream of droplets intersects the source flow, allowing for precise sorting of cells without breaking the cell stream into droplets, enabling operation at tens of kilohertz and maintaining sterility, and can be implemented in both microfluidic and traditional droplet cell sorters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional droplet-based cell sorting systems are used, then high throughput sorting (90,000 cells per second) is achieved, but biosafety is compromised due to aerosol generation

Engineering Contradiction:

Improvesorting throughputVSAvoidaerosol generation

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical droplet formation and charging system with an acoustically-driven liquid lens system. Acoustic waves focus the liquid stream to achieve sorting without mechanical droplet breakup or electrical charging, thereby eliminating aerosol generation while maintaining high throughput capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes acoustic phase transitions in the liquid stream to achieve focusing and sorting. By applying acoustic waves at specific frequencies, the liquid stream undergoes controlled phase transitions that enable precise cell positioning and sorting without generating harmful aerosols

Inventive Principle:

Principle #36Phase transitions

2Object-affected harmful factors

If microfluidic cell sorting devices are used, then biosafety and sterility are improved through closed systems, but sorting throughput is reduced to 1000-2000 cells per second

Engineering Contradiction:

ImprovebiosafetyVSAvoidsorting throughput

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent segments the liquid stream into controlled regions using acoustic focusing, allowing high-speed sorting within a closed microfluidic system. The acoustic field creates virtual segments that guide cells to different outlets without physical barriers, maintaining both biosafety and high throughput

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic acoustic waves to dynamically control cell sorting in real-time. The periodic modulation of acoustic frequency and amplitude enables rapid switching between different sorting modes, achieving high throughput while maintaining the closed-system biosafety of microfluidic devices

Inventive Principle:

Principle #19Periodic action

3Productivity

If traditional droplet cell sorters are used, then high sorting speed is achieved, but mechanical complexity and cost increase

Engineering Contradiction:

Improvesorting speedVSAvoidmechanical complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical droplet generation, charging, and deflection mechanisms with a unified acoustic field system. A single acoustic transducer array performs multiple functions (focusing, sorting, and guiding) that traditionally required separate mechanical components, thereby reducing overall system complexity while maintaining high sorting speed

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acoustic transducer array serves multiple functions simultaneously: it focuses the liquid stream, positions individual cells, directs them to appropriate outlets, and maintains flow stability. This multi-functionality eliminates the need for separate mechanical subsystems, reducing device complexity while preserving high throughput capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enables high-throughput, high-purity cell sorting at lower costs, eliminates the need for high shear forces and electrical charging, and allows for sorting in a completely closed environment, improving the efficiency and reliability of cell sorting, especially for biohazardous materials.

Implementation Method 1

a droplet generator positioned such that the droplets it generates intersect with the source flow

Methodology Applied

Scientific EffectFluid intersection and collision:

Data Source

PatentUS9470617B2Flow cytometry apparatus

Publication Date: 2016.10.18 SONY GROUP CORP

AI summary

A high speed fluid switch is used to separate desired particles from a source stream containing particles, such as cells. A droplet generator creates and regulates a stream of droplets, which intersects with a source stream containing the particles to be sorted. The stream of droplets can be regulated such that portions of the source stream containing desired particles are deflected into a collection vessel, or such that portions of the source stream containing desired particles are permitted to pass uninterrupted. The high speed fluid switch may be implemented on a microfluidic chip.