Dextran-Coated Magnetic Beads for High-Purity Cell Isolation

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Solution Overview

Problem

Current cell separation techniques face limitations in yield, purity, viability, and functionality of isolated cells, particularly in recovering rare cells and improving throughput.

Innovation Solution

The method employs a chromatographic approach optimized with a dextran molecule as a carrier for ligand binding partners like Strep-Tactin, achieving an avidity effect through polymerization/multimerization, and using bivalent tagging agents or linking molecules to enhance cell isolation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cell separation techniques are used, then cell isolation can be performed, but yield and purity of isolated cells are limited

Engineering Contradiction:
ImprovepurityVSAvoidyield
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention uses composite bead structures combining magnetic particles with dextran polymer coating. The magnetic core provides separation capability while the dextran shell provides binding sites for antibodies, creating a composite material that achieves both high purity through magnetic separation and high yield through enhanced cell binding capacity

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The dextran coating on magnetic beads creates a porous structure with high surface area and multiple binding sites. This porous matrix allows simultaneous binding of multiple antibodies per bead, increasing the efficiency of rare cell isolation while maintaining high purity through the magnetic separation mechanism

Inventive Principle:
Principle #31Porous materials

2Reliability

If conventional cell separation techniques are used, then cell isolation can be performed, but viability and functionality of isolated cells are compromised

Engineering Contradiction:
ImproveviabilityVSAvoidpurity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention replaces harsh mechanical filtration or centrifugation methods with gentle magnetic field-based separation. Cells bound to magnetic beads are separated by applying a magnetic field, which exerts minimal mechanical stress on cells compared to traditional methods, thereby maintaining high viability while achieving pure isolation

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

Solution Approach 2:

The magnetic beads act as intermediaries between the antibody binding and the separation process. Antibodies bind to cell surface antigens, which are then captured by the magnetic beads. This intermediary system allows pure separation through magnetic fields without direct mechanical manipulation of cells, preserving their viability and functionality

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional cell separation techniques are used, then isolation can be performed, but throughput and efficiency are limited

Engineering Contradiction:
ImprovethroughputVSAvoidpurity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention optimizes multiple parameters including bead size distribution, dextran coating thickness, antibody concentration, and magnetic field strength. These parameter optimizations enable high-throughput processing while maintaining pure separation, as the tuned parameters maximize binding efficiency and separation speed without compromising purity

Inventive Principle:
Principle #35Parameter changes

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 results in high yields and purity of isolated cells, such as CD4+ cells, while maintaining cell viability and functionality, and is particularly effective for isolating cells with low abundant surface antigens.

Implementation Method 1

achieve an avidity effect through polymerization/multimerization

Methodology Applied
Scientific EffectAvidity effect:

Implementation Method 2

providing at least two tagging agents (3) each comprising at least one binding domain (4) capable of specifically binding to the antigen (2) on the biological entity

Methodology Applied
Scientific EffectAntigen-antibody binding:

Implementation Method 3

the binding of the biological entity (1) via the tagging agent (3) to the carrier (11) and the binding of the linking molecule (10) via the tagging agent (3) to the carrier (11) and the binding of the linking molecule (10) to the stationary phase are mediated by non-covalent protein-ligand interaction

Methodology Applied
Scientific EffectNon-covalent protein-ligand interaction:

Implementation Method 4

purifying the biological entity (1) by a chromatographic procedure

Methodology Applied
Scientific EffectChromatography: Chromatography

Data Source

PatentEP4180811B1Methods of isolating a biological entity
Publication Date: 2025.04.09 CELL COPEDIA GMBH
  • EP4180811B1 patent drawingFigure 1
  • EP4180811B1 patent drawingFigure 2
  • EP4180811B1 patent drawingFigure 3

AI summary

Provided are affinity-based methods of isolating biological entities via a surface antigen from a sample with non-chromatographic and chromatographic methods being provided. Also provided is a dextran polymer, kits for use in the method of isolating a biological entity and an apparatus for performing the methods.