PDMS Microwell Array for Cell Sorting via Needle Release

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Solution Overview

Problem

Current cell sorting technologies face challenges in efficiently isolating adherent cells without damaging them, particularly due to the need for expensive optical systems and the limitations of existing microcarrier materials like photoresist arrays which have autofluorescence issues and complex fabrication requirements.

Innovation Solution

A cell sorting apparatus using an elastomeric substrate with microwells and detachable rafts made from materials like polystyrene, where cells adhere and are released using a needle, eliminating the need for expensive optical systems and simplifying fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If photoresist arrays are used as microcarriers, then cell sorting can be performed on adherent cells, but autofluorescence interferes with detection and fabrication is complex

Engineering Contradiction:
Improvecell sorting capabilityVSAvoidautofluorescence
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses inexpensive, disposable PDMS microwell arrays instead of expensive photoresist arrays. The PDMS substrates are readily available, low-cost, and can be discarded after use, eliminating the need for complex fabrication and cleaning procedures while avoiding autofluorescence issues

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

Solution Approach 2:

The patent changes the material parameter from photoresist to PDMS, which fundamentally alters the optical properties by eliminating autofluorescence and changes the surface properties to enable controlled cell adhesion and raft release

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If laser-based release systems are used, then precise pallet release can be achieved, but the optical system is expensive and requires precise alignment and maintenance

Engineering Contradiction:
Improvepallet release precisionVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the optical laser-based release system with a simple mechanical needle system. A thin needle physically pokes through the PDMS substrate to release individual rafts, eliminating the need for expensive lasers, beam splitters, mirrors, and complex alignment procedures while maintaining precise control over raft release

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

Solution Approach 2:

The PDMS substrate acts as a disposable mechanical component that can be easily pierced by a needle. After use, the entire substrate is discarded, eliminating the need for maintenance of complex optical systems

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

3Stability of the object's composition

If rigid substrates are used for cell carriers, then structural stability is maintained, but cell stress increases during release

Engineering Contradiction:
Improvesubstrate stabilityVSAvoidcell stress
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent uses a flexible PDMS substrate instead of a rigid substrate. The elastomeric nature of PDMS allows the substrate to deform elastically when a needle pokes through it, reducing mechanical stress on the cells during the release process while maintaining structural integrity before release

Inventive Principle:
Principle #30Flexible shells and thin films

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 allows for efficient, cost-effective isolation of adherent cells with high viability and flexibility in cell sorting criteria, overcoming the limitations of existing methods by using a simple, inexpensive needle-based release mechanism and reducing cell stress.

Implementation Method 1

said carriers are configured to release from said substrate upon mechanical distortion of said substrate

Methodology Applied
Scientific EffectMechanical distortion: Deformation

Implementation Method 2

said carriers are coated with a biologically active molecule... selected from the group consisting of... a cell adhesion molecule

Methodology Applied
Scientific EffectCell adhesion: Adhesive

Data Source

PatentEP2536819B1Array of micromolded structures for collecting or culturing of cells
Publication Date: 2024.12.18 THE UNIV OF NORTH CAROLINA AT CHAPEL HILL
  • EP2536819B1 patent drawingFigure 1A~2D
  • EP2536819B1 patent drawingFigure 3Ai~3E
  • EP2536819B1 patent drawingFigure 4

AI summary

An apparatus for collecting or culturing cells or cell colonies includes: a common substrate formed from a flexible resilient polymeric material and having a plurality of wells formed therein; and a plurality of rigid cell carriers releasably connected to said common substrate, with said carriers arranged in the form of an array, and with each of the carriers resiliently received in one of the wells. A method of collecting or culturing cells or cell colonies with such an apparatus is carried out by depositing a liquid media carrying cells on the apparatus so that said cells settle on or adhere to said the carriers; and then (c) releasing at least one selected carrier having said cells thereon by gradual application of release energy to each carrier from the cavity in which it is received (e.g., by pushing with a probe).