Parallel Microfluidic Cell Analysis Using Impedance Transit Sensing

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Solution Overview

Problem

Current methods for high-throughput mechanophenotyping of cells are limited by low throughput and high costs, particularly in systems that require high-speed cameras and complex image processing, making them unsuitable for widespread use due to financial and operational constraints.

Innovation Solution

A microfluidic device with parallel channels and an integrated multiplexed sensor network that quantifies cell transit times through constriction zones, utilizing a frequency division scheme to maximize throughput and minimize sensor idle time, allowing for continuous cell transit time measurement and scalable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-speed cameras and complex image processing are used for cell mechanophenotyping, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecell mechanophenotyping accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces optical measurement systems (high-speed cameras and image processing) with an electrical impedance-based sensing system. The sensor network uses electrical signals to detect cell transit times through microfluidic channels, eliminating the need for complex optical hardware and image processing algorithms while achieving comparable or superior measurement precision for cell mechanophenotyping

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

Solution Approach 2:

The patent uses electrical impedance signals as a simplified representation or 'copy' of cell mechanical properties. Instead of directly imaging and analyzing cell deformation with cameras, the system measures electrical impedance changes that correlate with cell transit time and mechanical characteristics, providing an indirect but effective measurement approach

Inventive Principle:
Principle #26Copying

2Measurement precision

If high-speed cameras and image processing are used, then measurement precision is improved, but cost increases

Engineering Contradiction:
Improvecell mechanophenotyping accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent substitutes expensive optical measurement equipment with cost-effective electrical impedance sensors. The sensor network uses standard electrical components to measure cell transit times, dramatically reducing system cost while maintaining measurement precision for cell mechanophenotyping applications

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

Solution Approach 2:

The patent employs inexpensive electrical impedance sensors that can be easily manufactured and integrated into microfluidic devices. These sensors use simple electrical components rather than expensive camera systems, making the overall system more affordable and suitable for widespread deployment

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

3Productivity

If parallel channels with sensor networks are used, then productivity is improved, but device complexity increases

Engineering Contradiction:
ImprovethroughputVSAvoidsensor network complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the measurement system into multiple parallel microfluidic channels, each with dedicated sensor pairs. This segmentation allows simultaneous measurement of multiple cells across different channels, increasing throughput while keeping each individual channel-simple and manageable

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a universal sensor design where identical sensor pairs are replicated across multiple channels. Each sensor pair performs the same function of measuring transit time, and the data from all channels are processed using the same algorithm, simplifying the overall system architecture despite the increased number of components

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If continuous cell transit time measurement is implemented, then productivity is improved, but loss of time decreases (less idle time)

Engineering Contradiction:
ImprovethroughputVSAvoidsensor idle time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements continuous measurement by having multiple sensor pairs distributed along parallel channels that operate simultaneously. As cells flow continuously through the system, each sensor pair continuously detects transit events, eliminating idle time between measurements and maximizing productivity

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent positions sensor pairs upstream and downstream of constriction zones before cells actually pass through them. This preliminary positioning allows the system to detect and record transit times continuously as cells approach and pass through the measurement zones, ensuring no measurement gaps occur

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

The solution achieves high-throughput cell mechanophenotyping while reducing costs and operational complexity, enabling efficient mechanical characterization of cells with minimal idle time and consistent delivery, comparable to Coulter counter performance.

Implementation Method 1

an integrated multiplexed sensor network that quantifies cell transit times through constriction zones

Methodology Applied
Scientific EffectElectrical impedance sensing: Electrical Resistance

Data Source

PatentEP3866975B1Massively parallel microfluidic cell analyzer for high throughput mechanophenotyping
Publication Date: 2024.06.26 GEORGIA TECH RES CORP
  • EP3866975B1 patent drawingFigure 1
  • EP3866975B1 patent drawingFigure 2
  • EP3866975B1 patent drawingFigure 3~4

AI summary

A microfluidic device may include an inlet, an outlet, first and second channels arranged in parallel, a first sensor pair positioned along the first channel, and a second sensor pair positioned along the second channel. The first channel may include a first upstream zone, a first downstream zone, and a first constriction zone. The second channel may include a second upstream zone, a second downstream zone, and a second constriction zone. The first sensor pair may include a first entry sensor configured to detect a first cell flowing through the first upstream zone, and a first exit sensor configured to detect the first cell flowing through the first downstream zone. The second sensor pair may include a second entry sensor configured to detect a second cell flowing through the second upstream zone, and a second exit sensor configured to detect the second cell flowing through the second downstream zone.