Double-Layer Tube With Porous Membrane For Plasma Separation

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Solution Overview

Problem

Existing blood collection devices often face issues with insufficient differential pressure for complete plasma/serum separation, clogging of separation filters, and contamination of separated plasma/serum during removal.

Innovation Solution

A fluid sample collection device comprising an evacuated outer container and an inner container with a porous membrane that separates plasma or serum from blood cells, allowing for efficient plasma/serum separation at the site of sample collection by establishing a pressure differential and preventing cell transfer through the membrane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a filter with sufficiently small pore size is used to prevent cellular components from passing through, then plasma separation effectiveness is improved, but the filter becomes clogged during blood collection and plasma separation

Engineering Contradiction:
Improveplasma separation effectivenessVSAvoidfilter clogging
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention divides the collection device into separate chambers: an outer container for blood collection and an inner container for plasma collection, separated by a membrane. This segmentation allows the filter membrane to be positioned at the interface between chambers, preventing cell passage while maintaining plasma flow through the pressure differential created by evacuation of the inner container.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a porous membrane as an intermediary barrier between the outer container containing blood cells and the inner container for plasma collection. This membrane acts as a selective filter that allows plasma to pass through while blocking cellular components, resolving the contradiction between effective separation and filter clogging.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If vacuum force is increased to draw plasma from collected blood sample, then plasma separation speed is improved, but the vacuum force becomes inadequate when filter is clogged

Engineering Contradiction:
Improveplasma separation speedVSAvoidvacuum force adequacy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The inner container is pre-evacuated to create a pressure differential before blood collection begins. This preliminary action establishes the driving force for plasma separation in advance, ensuring that when plasma needs to be drawn through the membrane, adequate pressure differential is already present to overcome filter resistance without requiring additional vacuum force increases.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If centrifugation is used to separate plasma from blood cells, then complete separation is achieved, but the device complexity and time required increase

Engineering Contradiction:
Improvecomplete separationVSAvoidseparation method complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces the mechanical centrifugation system with a pressure differential-based separation system. Instead of using centrifugal force generated by rotation, the device uses the pressure difference created by evacuating the inner container to drive plasma through the porous membrane, achieving complete separation without the complexity of centrifugation equipment.

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

Solution Approach 2:

The invention employs pneumatic principles by using vacuum pressure applied to the inner container to draw plasma through the membrane from the outer container. This pneumatic approach replaces the mechanical centrifugation method, simplifying the device while achieving complete plasma-se cell separation through pressure-driven flow.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 enables rapid and effective separation of plasma or serum from blood samples, reducing contamination risks and ensuring complete separation with minimal filter clogging, allowing for efficient plasma or serum collection and analysis.

Implementation Method 1

a porous filter also referred to as a membrane herein... the separating filter or membrane has a sufficiently small pore size to prevent cellular components from passing through the filter or membrane while allowing the passage of liquid

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

evacuated multi-chamber devices... typical vacuum forces generated by the evacuated device inadequate to draw plasma from a collected blood sample... a pressure differential is created between the upstream tube and the downstream tube

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP2046499B1Membrane-based double-layer tube for sample collections
Publication Date: 2017.11.15 BECTON DICKINSON & CO
  • EP2046499B1 patent drawingFigure 1~3
  • EP2046499B1 patent drawingFigure 4~5
  • EP2046499B1 patent drawingFigure 6~7

AI summary

The fluid sample collection device is adapted to collect and separate a fluid sample into constituent parts such as separating plasma or serum from a blood sample. The device includes an evacuated outer container and an inner container. The outer container has a first open end and a second closed end. A pierceable closure closes the first open end thereby defining a first interior chamber. The inner container is contained within the outer container and separates the first interior chamber into an upper chamber portion and lower chamber portion in fluid communication. The inner container defines a second interior chamber separated from the lower chamber portion through a porous membrane. A port is provided for placing the second interior chamber in fluid communication with the first interior chamber. Another aspect of the device relates to a method of using the device to separate plasma or serum from a blood sample.