Extracellular Vesicle Isolation Using Polycation and Polymer Precipitation
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Solution Overview
Problem
Current methods for isolating extracellular vesicles (EVs) from biological fluid samples are inefficient, often damage the vesicles, and require expensive equipment, making it difficult to recover sufficient amounts from small samples while also dealing with contamination and integrity issues.
Innovation Solution
A method involving the use of a polycationic substance like protamine in combination with an extracellular matrix forming polymer, such as PEG, to precipitate EVs without the need for ultracentrifugation, facilitating efficient recovery and maintaining biological activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If differential ultracentrifugation is used to isolate EVs, then purification efficiency is improved, but EV integrity is damaged and equipment cost increases
Solution Approach 1:
The patent replaces the mechanical ultracentrifugation system with a chemical precipitation system using PEG and protamine. Instead of using high-speed rotation and centrifugal force to separate EVs, the invention uses polymeric precipitation to form a mesh-like net that embeds EVs, thereby avoiding shear stress and mechanical damage while achieving efficient isolation.
Solution Approach 2:
The invention changes the isolation parameters from mechanical force-based (centrifugal force, g force, rotor type) to chemical composition-based (PEG concentration, protamine concentration, molecular weight). This parameter change allows efficient EV isolation without the damaging effects of ultracentrifugation.
2Productivity
If differential ultracentrifugation is used to isolate EVs, then purification efficiency is improved, but equipment cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical ultracentrifugation system with a chemical precipitation system using PEG and protamine. Instead of using high-speed rotation and centrifugal force to separate EVs, the invention uses polymeric precipitation to form a mesh-like net that embeds EVs, thereby avoiding shear stress and mechanical damage while achieving efficient isolation.
Solution Approach 2:
The invention uses inexpensive chemical reagents (PEG and protamine) instead of expensive ultracentrifugation equipment. The precipitation method can be performed with simple mixing and low-speed centrifugation, eliminating the need for costly ultracentrifuges and reducing device complexity.
3Loss of time
If polymeric precipitation with PEG is used to isolate EVs, then isolation speed is improved, but EV recovery efficiency from small samples is insufficient
Solution Approach 1:
The patent uses a composite precipitation system combining PEG (polyethylene glycol) and protamine. PEG forms the mesh-like net structure that embeds EVs, while protamine enhances the precipitation efficiency and EV recovery. This composite approach maintains the speed advantage of polymeric precipitation while significantly improving EV recovery from small biological samples.
Solution Approach 2:
Protamine acts as an intermediary that enhances the interaction between PEG and EVs. The polycationic nature of protamine facilitates binding to the negatively charged EV surface, improving precipitation efficiency and recovery amount without sacrificing isolation speed.
4Loss of time
If conventional polymeric precipitation is used to isolate EVs, then isolation speed is improved, but contamination and loss of biological activity occur
Solution Approach 1:
The patent uses a composite precipitation system combining PEG (polyethylene glycol) and protamine. PEG forms the mesh-like net structure that embeds EVs, while protamine enhances the precipitation efficiency and EV recovery. This composite approach maintains the speed advantage of polymeric precipitation while significantly improving EV recovery from small biological samples.
Solution Approach 2:
The invention changes the isolation parameters from mechanical force-based (centrifugal force, g force, rotor type) to chemical composition-based (PEG concentration, protamine concentration, molecular weight). This parameter change allows efficient EV isolation without the damaging effects of ultracentrifugation.
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 effectively isolates EVs from small biological samples with improved integrity and biological activity, avoiding the need for expensive equipment and reducing contamination, while maintaining RNA recovery and exosomal marker expression.
Implementation Method 1
The polymeric precipitation methods are based on the formation of a mesh-like net, which embeds EVs with a size ranging from 60 to 180 nm
Implementation Method 2
mixing the biological fluid sample with a polycationic substance and an extracellular matrix forming polymer, incubating the resulting mixture, thereby achieving precipitation of EVs
Data Source
AI summary
The invention relates to compositions and methods for isolating extracellular vesicles (EVs) from a biological fluid sample. The compositions and methods of the invention are based on the combination of a polycation with an extracellular matrix forming polymer. Extracellular vesicles (EVs) are isolated from biological fluids such as blood, serum, plasma, saliva, urine or cerebrospinal fluid, or from the conditioned medium of a cell culture, such as an adult stem cell culture. The use of the isolation methods and compositions of the invention results in a higher EVs recovery, enrichment in exosomes, simplicity, cost-effectiveness, and in the isolation of EVs that retain their biological activities in vitro.