Cascade Ultrafiltration for Extracellular Vesicle Isolation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for isolating extracellular vesicles, such as exosomes, from biological fluids are either labor-intensive, time-consuming, or result in contamination with cellular and protein debris, making them unsuitable for standard diagnostic laboratories.

Innovation Solution

A two-stage filtration method using membrane filters with specific pore sizes (400-600 nm and 95-200 nm) that do not bind biological polymers, allowing for the efficient isolation of intact extracellular vesicles without the need for ultracentrifugation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If ultracentrifugation is used to isolate exosomes, then the isolated fraction is obtained, but it is contaminated by cellular and protein debris

Engineering Contradiction:

Improveexosome isolationVSAvoidcontamination with cellular and protein debris

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The isolation process is divided into multiple sequential filtration stages with different pore sizes (0.22 μm, 0.1 μm, 0.03 μm) to progressively separate exosomes from contaminants of different sizes, achieving purification without ultracentrifugation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each filtration stage uses membranes with specific pore sizes tailored to remove particular contaminants while preserving exosomes, with the final stage using 0.03 μm pores to capture exosomes while excluding smaller protein debris

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If gradient ultracentrifugation is used to increase purity of exosomal fraction, then purity is improved, but the method is labor and time-consuming and results in loss of exosomes

Engineering Contradiction:

Improvepurity of exosomal fractionVSAvoidlabor and time consumption

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent replaces the complex mechanical ultracentrifugation system with a simpler filtration system using vacuum or gravity-driven passage through sequential membrane filters, dramatically reducing time and labor while maintaining effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the separation parameter from density-based ultracentrifugation to size-based filtration, using membranes with progressively smaller pore sizes to isolate exosomes, achieving high purity without the time-consuming ultracentrifugation process

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If polyethylene glycol precipitation is used to isolate exosomes, then the isolation is less labor consuming, but cell debris and protein fractions are precipitated along with exosomes

Engineering Contradiction:

Improvelabor consumptionVSAvoidcontamination with cell debris and protein fractions

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent uses porous membrane filters with specifically controlled pore sizes (0.22 μm, 0.1 μm, 0.03 μm) to physically separate exosomes from contaminants based on size differences, avoiding the non-selective precipitation caused by polyethylene glycol while maintaining ease of operation

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

Each filtration stage uses membranes with specific pore sizes tailored to remove particular contaminants while preserving exosomes, with the final 0.03 μm membrane providing selective capture of exosomes while excluding smaller protein fractions that would otherwise co-precipitate

Inventive Principle:

Principle #3Local quality

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 method provides a simple, fast, and highly effective means of purifying extracellular vesicles, reducing contamination and preserving their integrity for diagnostic and therapeutic applications in standard diagnostic laboratories.

Implementation Method 1

filter the sample of biological fluid at least once through the first membrane filter containing a membrane that practically does not bind biological polymers and has pore sizes in the range from 400-600 nm; filter the solution obtained from step (b) at least once through the second membrane filter containing a membrane that practically does not bind biological polymers and has pore sizes ranging from 100-200 nm

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentUS11260347B2Method and device for separating extracellular vesicles from biological liquids with the aid of cascade ultrafiltration

Publication Date: 2022.03.01 LLC PROSTAGNOST

AI summary

This invention describes a method and a device for efficient isolation of extracellular vesicles from animal and human biological fluids, as well as from culture fluid using equipment of standard diagnostic laboratories, that is, without the use of ultracentrifugation. These method and device can be applied for the diagnosis of various human diseases, as well as for therapeutic purposes, if the purified vesicles are used as an agent for drug delivery to the cells of the body. The device for the purification of extracellular vesicles contains at least two membrane filters: the first filter containing a membrane with pore sizes in the range from 400 to 600 nm, connected to the second filter containing a membrane with pores in the range from 95 to 200 nm. At the same time, the membranes of these filters are made of materials that practically do not bind biological polymers.