Closed-System Flow Cell with Herringbone Grooves for Tissue Staining

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Solution Overview

Problem

Conventional open systems for tissue slide staining are inefficient due to slow reagent diffusion, reagent evaporation, and wicking issues, leading to low staining rates and increased costs.

Innovation Solution

A closed-system flow cell system with a herringbone groove pattern that creates a chaotic advection regime for enhanced reagent mixing and temperature control, preventing evaporation and allowing clear visualization of the slide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If molecular diffusion is relied upon for reagent flow across the slide surface in open systems, then the system structure is simple, but the staining rate is slow

Engineering Contradiction:
Improvestaining rateVSAvoidsystem structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs a fluid delivery system with channels and reservoirs to transport reagents across the slide surface, replacing passive molecular diffusion with active hydraulic flow. The channel network guides reagent movement from reservoirs through defined paths to the slide, enabling controlled and accelerated delivery that significantly improves staining rate while maintaining reasonable system complexity through integrated microfluidic structures.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If reagents are exposed to air in open systems, then the system structure is simple, but reagent evaporation increases leading to tissue drying

Engineering Contradiction:
Improveprevention of tissue dryingVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a closed system where reagents flow through enclosed channels and reservoirs, creating an inert environment that isolates reagents from atmospheric exposure. This prevents evaporation and maintains stable chemical conditions throughout the staining process, ensuring reliable prevention of tissue drying. The sealed microfluidic architecture eliminates air contact while maintaining functional simplicity through integrated channel designs.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Reliability

If reaction covers are used to create a closed environment, then reagent evaporation is reduced, but the view of the slide is obscured

Engineering Contradiction:
Improveprevention of reagent evaporationVSAvoidvisibility of slide
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent replaces opaque reaction covers with transparent microfluidic channels that allow visual observation of the slide while maintaining a closed environment. The channel structure provides evaporation protection through sealing while its transparent material enables continuous monitoring of the staining process. This hydraulic enclosure system simultaneously achieves both protection and visibility that neither open systems nor traditional covers can provide.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Productivity

If reagents flow rapidly across the slide, then staining rate improves, but reagent wicking to different sides causes quality issues

Engineering Contradiction:
Improvestaining rateVSAvoidstain quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the reagent delivery path into defined channels with controlled geometry, separating the flow paths to prevent unwanted wicking. The channel network divides reagent flow into discrete, guided streams that maintain precise spatial control across the slide surface. This segmentation prevents lateral wicking while preserving rapid forward flow, enabling high staining rates with uniform quality by confining reagents to their intended pathways.

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 system significantly enhances reagent mixing and prevents evaporation, improving staining efficiency and reducing costs by maintaining a controlled environment for reagents, while allowing for clear observation of the slide.

Implementation Method 1

the groove pattern provides a chaotic advection regime to fluid within the channel

Methodology Applied
Scientific EffectChaotic advection: Advection

Implementation Method 2

The closed system of the flow cell system of the present invention helps enhance fluid mixing and prevents reagent evaporation

Methodology Applied
Scientific EffectEvaporation prevention: Evaporation

Data Source

PatentEP3374752B1Closed-system passive mixing flow cell system for tissue slide staining
Publication Date: 2023.08.09 VENTANA MEDICAL SYSTEMS INC
  • EP3374752B1 patent drawingFigure 1
  • EP3374752B1 patent drawingFigure 2
  • EP3374752B1 patent drawingFigure 3A

AI summary

A closed-system flow cell system featuring an encasement with an inner cavity adapted to hold a slide and form a channel atop the slide. The encasement comprises a groove pattern within the channel, wherein the groove pattern provides a chaotic advection regime to fluid within the channel. The flow cell system helps enhance fluid mixing and prevent reagent evaporation and drying out of the tissue.