Curvilinear Cavity Microfluidic Device for Cell Sorting

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Solution Overview

Problem

Existing microfluidic devices face challenges in maintaining consistent hydrodynamic resistance and flow velocity over time, leading to clogging issues during cell sorting and microcell culture, particularly when dealing with diverse cell populations and requiring precise control over cell density and signaling responses.

Innovation Solution

A microfluidic device with curvilinear cavities and a gas expansion molding technique is developed, featuring a substrate with spherical or oblong cavities that expand outward from a rounded bottom, allowing for variable maximum diameters and coatings for selective cell capture, along with embedded sensors for real-time diagnostics, enabling efficient cell sorting and culture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pillar arrays are used for cell separation, then cell sorting capability is improved, but hydrodynamic resistance changes over time causing clogging

Engineering Contradiction:

Improvecell sorting capabilityVSAvoidhydrodynamic resistance stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces traditional pillar structures with curvilinear cavities that have smooth, rounded contours. This curvature eliminates sharp edges where cells can become trapped, allowing cells to flow through without adhering to the channel walls, thereby maintaining stable hydrodynamic resistance while preserving cell sorting functionality.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Instead of using protruding pillars that cells must navigate around (which create clogging points), the invention inverts the approach by using recessed curvilinear cavities. This inversion allows cells to pass through the channel center without contacting the channel boundaries, eliminating the clogging mechanism while maintaining separation capability.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If curvilinear cavities with maximum diameter greater than opening diameter are used, then cell capture and adhesion are enhanced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecell capture efficiencyVSAvoidcavity geometry control

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent specifies particular parameter ranges for the curvilinear cavities, including the ratio of maximum diameter to opening diameter being greater than 1, and the maximum diameter being in the range of 60-200 microns while opening diameter is 150-350 microns. These parameter definitions provide design guidance that balances cell capture efficiency with manufacturability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The curvilinear cavity design with smooth curved surfaces rather than sharp geometric features simplifies the manufacturing process. The continuous curved geometry can be fabricated using standard soft lithography and molding techniques without requiring ultra-precise feature definition, thus reducing manufacturing precision requirements while maintaining effective cell capture.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If devices are designed for diverse cell population sorting, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improvecell population diversity handlingVSAvoidchannel and cavity configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The curvilinear cavity design serves multiple functions simultaneously: it enables cell separation based on size and density, provides attachment surfaces for cell culture, and maintains stable flow characteristics. This multi-functionality allows a single device configuration to handle diverse cell populations without requiring complex additional structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The device divides the cell sorting function into multiple curvilinear cavities arranged in arrays, where each cavity acts as an independent sorting unit. This segmentation allows diverse cell populations to be sorted through simple geometric principles rather than complex multi-stage processing, reducing overall device complexity while maintaining high adaptability.

Inventive Principle:

Principle #1Segmentation

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 device effectively integrates cell sorting, microcell culture, and diagnostics, providing a stable and controlled environment for cell studies, including rare cell sorting and stem cell research, while minimizing clogging issues and enhancing cell proliferation and adhesion.

Implementation Method 1

Gas dissolved in the polymer premix is expanded to form microbubbles

Methodology Applied

Scientific EffectGas expansion: Thermal Expansion

Data Source

PatentUS9457497B2Microfluidic device and method of manufacturing the microfluidic device

Publication Date: 2016.10.04 UNIVERSITY OF ROCHESTER

AI summary

A microfluidic device having a substrate with an array of curvilinear cavities. The substrate of the microfluidic device is preferably fabricated of a polymer such as polydimethylsiloxane. The microfluidic device is manufactured using a gas expansion molding technique.