Microvesicle Isolation via PEG Precipitation

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Solution Overview

Problem

Current methods for isolating microvesicles, such as ultracentrifugation and size exclusion chromatography, are labor-intensive, time-consuming, and costly, and often require expensive equipment, while existing immunoaffinity capture methods have low yields and are costly due to the use of reagents and magnetic beads.

Innovation Solution

The use of polyethylene glycol (PEG) precipitation solutions with molecular weights of 8,000 or 10,000 Daltons to isolate microvesicles from liquid samples, including biofluids and cell culture media, through a low-speed centrifugation process that does not require high-speed centrifugation equipment, allowing for the production of microvesicle-depleted serum suitable for cell culture media.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If ultracentrifugation is used to isolate microvesicles, then isolation purity is improved, but device complexity and cost increase

Engineering Contradiction:

Improveisolation purityVSAvoidequipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical ultracentrifugation system with a chemical precipitation system using PEG. Instead of using high-speed centrifugal force to separate microvesicles, the invention uses polyethylene glycol to precipitate microvesicles from body fluids through chemical interaction, thereby eliminating the need for expensive ultracentrifuge equipment while maintaining isolation purity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the isolation parameter from physical force (centrifugal force in ultracentrifugation) to chemical property (PEG precipitation). By using PEG with specific molecular weights (8,000-10,000 Daltons), the invention creates a chemical basis for separation that does not require high-speed centrifugation, thus simplifying equipment requirements while maintaining separation effectiveness.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If size exclusion chromatography is used to isolate microvesicles, then isolation purity is improved, but time consumption and cost increase

Engineering Contradiction:

Improveisolation purityVSAvoidisolation time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the size exclusion chromatography system with a simple precipitation system. Instead of using chromatographic columns and complex separation mechanisms that require extended run times, the invention uses PEG precipitation that can be performed in a single step with rapid centrifugation, dramatically reducing isolation time while maintaining purity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If immunoaffinity capture is used to isolate microvesicles, then isolation specificity is improved, but yield decreases and cost increases

Engineering Contradiction:

Improveisolation specificityVSAvoidisolation yield

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent uses PEG as a simple, inexpensive, and reusable precipitation agent instead of expensive immunoaffinity reagents and magnetic beads. The PEG method eliminates the need for costly antibodies and bead conjugates, providing a cost-effective solution that maintains high isolation yield without sacrificing specificity.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 enables rapid and inexpensive isolation of microvesicles with high yields, confirmed by protein markers and size analysis, and produces serum depleted of endogenous microvesicles, supporting cell growth without interfering with experimental results.

Implementation Method 1

The use of polyethylene glycol (PEG) precipitation solutions with molecular weights of 8,000 or 10,000 Daltons to isolate microvesicles from liquid samples

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Implementation Method 2

through a low-speed centrifugation process that does not require high-speed centrifugation equipment

Methodology Applied

Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentUS9005888B2Methods for microvesicle isolation and selective removal

Publication Date: 2015.04.14 SYSTEM BIOSCIENCES LLC

AI summary

The invention relates to compositions and methods for isolation of microvesicles produced by mammalian cells. These microvesicles, known as extracellular microvesicles or circulating microvesicles, are isolated from sample materials such as body fluids, or from cell culture media that has been used to culture and maintain mammalian cells in vitro. The isolation of microvesicles as described herein results in purification and concentration of the microvesicles.The invention also provides related methods for producing blood serum and/or blood plasma that is free of detectable microvesicles, largely depleted of microvesicles, or has reduced concentration of microvesicles compared to the blood serum or blood plasma starting material (collectively termed “microvesicle-depleted”). The generation of microvesicle-depleted blood serum or plasma is critical for use in experimental systems where it is desirable to use a cell culture media that does not contain endogenous microvesicles, or has been depleted of endogenous microvesicles, from the source material.