MEMS Particle Sorting Chip with Disposable Actuator

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Solution Overview

Problem

Current methods for sorting hematopoietic stem cells from blood samples are limited by low throughput, high cost, and disposability issues, making them inefficient and expensive for clinical use.

Innovation Solution

A microelectromechanical systems (MEMS) particle sorting chip with a fluid channel and MEMS actuators that detect fluorescent markers to sort cells into separate pathways, using an electromagnetic actuator optimized for speed and cost-effectiveness, allowing for high-throughput and disposable system design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If flow cytometry is used to sort hematopoietic stem cells, then purity of sorted cells is improved, but throughput is limited and cost is high

Engineering Contradiction:
Improvepurity of sorted cellsVSAvoidthroughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The device segments the fluid stream into discrete droplets, with each droplet containing at most one cell. This segmentation allows parallel processing of multiple cells simultaneously through multiple actuators, dramatically increasing throughput while maintaining the precision of individual cell sorting through fluorescence detection of each droplet

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from serial cell-by-cell sorting to parallel batch processing by introducing the spatial dimension of multiple droplets flowing simultaneously through multiple channels. Each droplet is independently actuated by corresponding MEMS actuators, enabling high-throughput sorting while maintaining individual cell resolution through the droplet discretization approach

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

2Productivity

If conventional sorting equipment is used, then cell sorting can be performed, but the system is expensive and difficult to dispose or sterilize

Engineering Contradiction:
Improvecell sorting capabilityVSAvoiddisposability and cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The device is designed as a disposable single-use unit fabricated using standard MEMS processes. The entire sorting chip including fluid channels, actuators, and detection structures can be manufactured cheaply in batches and discarded after a single use, eliminating costly sterilization requirements and reducing cross-contamination risks

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention replaces complex mechanical sorting mechanisms with integrated MEMS actuators that can be fabricated using standard semiconductor manufacturing processes. This substitution enables mass production at low cost and simplifies the overall system architecture, making disposability economically viable

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

3Productivity

If faster sorting is achieved by increasing pressure, then throughput is improved, but cell viability is reduced

Engineering Contradiction:
Improvesorting speedVSAvoidcell viability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By segmenting cells into individual droplets, the system can apply actuation forces to each droplet independently at optimal moments during flight. This eliminates the need for continuous high pressure, as sorting decisions are made and executed in discrete time windows, reducing overall pressure requirements and protecting cell viability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sorting process uses periodic actuation of MEMS actuators synchronized with the droplet flight time. Each actuator fires briefly when its corresponding droplet passes the decision point, then returns to neutral. This periodic, pulsed action achieves high sorting speeds without requiring sustained high pressure that would damage cells

Inventive Principle:
Principle #19Periodic 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

The MEMS particle sorting chip significantly increases throughput, reduces costs, and addresses disposability concerns, enabling efficient and cost-effective sorting of hematopoietic stem cells with high purity.

Implementation Method 1

an electromagnetic actuator optimized for speed and cost-effectiveness

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

detect fluorescent markers to sort cells into separate pathways

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP1941254B1MEMS actuator and method of manufacture for MEMS particle sorting device
Publication Date: 2011.11.23 INNOVATIVE MICRO TECH
  • EP1941254B1 patent drawingFigure 1
  • EP1941254B1 patent drawingFigure 2
  • EP1941254B1 patent drawingFigure 3

AI summary

A micromechanical particle sorting chip uses an actuator divided into two parts to direct a component of interest into one of a plurality of possible exit paths, based on detection of a fluorescent signal emanating from the component of interest. The two-part actuator may include a force-generating portion (350) and a microactuator portion (330). The microactuator portion (330) may be disposable, whereas the force-generating portion (350) may be reuseable. By bringing the force-generating portion (350) into proximity to the microactuator portion (330), the microactuator (300) is induced to move, thereby separating the component of interest from the rest of the fluid stream. The force-generating portion (350) and the microactuator portion (330) may be optimized and fabricated separately, thereby leading to faster, more reliable and less expensive particle sorting.