Drop-Carrier Particle Structures for Uniform Single-Cell Droplets

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Solution Overview

Problem

Current methods for single-molecule or single-cell assays face challenges in uniformly compartmentalizing small volumes without complex microfluidic instruments, and introducing solid supports or unique barcodes is difficult, leading to inefficiencies and high costs.

Innovation Solution

The development of sub-millimeter scale drop-carrier particles with well-defined 3D structures and chemical functionalities that create monodisperse droplet volumes, allowing for compartmentalization and association with solid supports, enabling reactions without microfluidics, and using sculpted microfluidic flows to fabricate Janus particles that stabilize aqueous droplets in an oil phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If microfluidic approaches are used to create monodisperse emulsions, then uniform droplet volumes are achieved, but high instrument cost and complexity are incurred

Engineering Contradiction:
Improveuniform droplet volumesVSAvoidmicrofluidic instruments
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses disposable microwell arrays with hydrophobic coatings that can be easily discarded after use. This eliminates the need for expensive, complex microfluidic instruments while achieving uniform droplet volumes through the predefined well geometry and hydrophobic surface properties that prevent droplet coalescence.

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

Solution Approach 2:

The patent replaces the mechanical microfluidic pumping and flow control systems with a static microwell array system. Uniform droplet formation is achieved through the geometric constraints of the microwells and hydrophobic surface chemistry rather than through active mechanical control of fluid flow.

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

2Productivity

If microfluidic pumping systems are used, then droplet formation is achieved, but large dead-volumes limit small sample volume usage

Engineering Contradiction:
Improvedroplet formation capabilityVSAvoidsmall sample volumes
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the sample into individual microwells, each containing a single droplet. This segmentation approach eliminates the need for large dead-volumes in pumping systems because the sample is partitioned into many small, discrete reaction compartments, allowing efficient use of minimal sample volumes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses thin hydrophobic film coatings on the microwell surfaces to contain the droplets. This thin-film approach minimizes the volume of reagents and sample required compared to bulk microfluidic channels, enabling effective use of small sample volumes while maintaining droplet formation capability.

Inventive Principle:
Principle #30Flexible shells and thin films

3Adaptability or versatility

If solid supports with reagents and barcodes are introduced into microwell arrays, then digital ELISA and single-cell RNAseq are enabled, but Poisson statistics limitations arise

Engineering Contradiction:
Improveassay capabilityVSAvoiduniform compartmentalization
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent pre-loads solid supports with reagents and barcodes into the microwells before adding the sample. This preliminary action ensures that each compartment is properly prepared with the necessary components, enabling digital ELISA and single-cell RNAseq assays while maintaining uniform compartmentalization by avoiding post-loading variations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent designs the system so that the solid supports themselves provide the necessary reagents and barcodes without requiring external intervention during the assay. This self-service approach reduces variability introduced by manual loading operations and maintains uniform compartmentalization while enabling versatile assay capabilities.

Inventive Principle:
Principle #25Self-service

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 enables cost-effective, uniform compartmentalization of droplets compatible with standard equipment, facilitating single-molecule and single-cell assays with ease of use and compatibility with standard benchtop workflows, reducing the need for complex instruments.

Implementation Method 1

The interior region 14 of the drop-carrier particle 12 is, in one exemplary embodiment, hydrophilic. The exterior region 16 of the drop-carrier particle 12 is, in one exemplary embodiment, hydrophobic.

Methodology Applied
Scientific EffectHydrophile-Hydrophobe interaction: Hydrophobe

Implementation Method 2

sculpted microfluidic flows to fabricate Janus particles that stabilize aqueous droplets in an oil phase

Methodology Applied
Scientific EffectMicrofluidic flow: Laminar Flow

Implementation Method 3

The combined drop-carrier particle with the dispersed phase (e.g., aqueous phase) contained therein is referred to as a particle-drop. The selective association results in compartmentalization of the dispersed phase solution into sub-microliter-sized volumes

Methodology Applied
Scientific EffectPhase separation: Emulsion

Data Source

PatentEP4455301B1Particle-drop structures and methods for making and using the same
Publication Date: 2026.04.08 RGT UNIV OF CALIFORNIA
  • EP4455301B1 patent drawingFigure 1
  • EP4455301B1 patent drawingFigure 2A~2C
  • EP4455301B1 patent drawingFigure 3A~4C

AI summary

The invention is directed to a particle system comprising a plurality of three-dimensional particles, each particle having an interior region defining a three-dimensional cavity or void and an exterior region, wherein the cavity or void is open to an external environment of the three-dimensional particle and wherein the cavity or void has a volume between about 1 pL and about 125 nL and a molecular capture region disposed on the interior region of the particles configured to capture cells, and to a method of performing an assay using the particle system.