Thermoresponsive Polymer UCST Lowering Agent Storage

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Solution Overview

Problem

Thermoresponsive magnetic particles used for biomolecule separation often require heating above their lower critical solution temperature (LCST), which can damage or inactivate target substances, and thermoresponsive microparticles with upper critical solution temperature (UCST) stored at low temperatures may aggregate and fail to disperse upon heating.

Innovation Solution

A method involving the use of an upper critical solution temperature (UCST) lowering agent, such as sodium chloride or dimethyl sulfoxide, to maintain thermoresponsive polymers and particles in a dissolved or dispersed state at storage temperatures below their UCST, preventing aggregation and maintaining ligand activity over long periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If thermoresponsive magnetic particles with LCST are heated above LCST for separation, then aggregation occurs enabling easy collection by magnetic force, but target biomolecules may be damaged or inactivated

Engineering Contradiction:

Improveseparation efficiencyVSAvoidbiomolecule damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from heating above LCST to cooling below UCST. By using a polymer with UCST and storing/operating below this temperature, the system achieves aggregation for separation without heating that would damage biomolecules, thus resolving the contradiction between separation efficiency and biomolecule integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of heating to cause aggregation (LCST mechanism), the patent inverts the approach by cooling to cause aggregation (UCST mechanism). This reversal allows aggregation and magnetic collection to occur at low temperatures that preserve biomolecule activity, solving the harmful heating effect

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If thermoresponsive microparticles with UCST are stored at low temperature (0-10°C) to preserve ligand activity, then ligand damage is prevented, but the polymer aggregates and may not disperse upon heating

Engineering Contradiction:

Improveligand stabilityVSAvoidpolymer dispersion state

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by adding a dispersant before storage. This dispersant pre-establishes steric or electrostatic barriers that prevent aggregation during low-temperature storage, ensuring the polymer remains dispersed and ready for rapid redispersion when needed, thus resolving the contradiction between ligand stability and polymer dispersion

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dispersant acts as an intermediary substance that mediates between the polymer and the storage environment. It provides steric or electrostatic stabilization that prevents aggregation at low temperatures while maintaining ligand activity, solving the contradiction between preserving ligand stability and maintaining polymer dispersion

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach allows for the stable storage of thermoresponsive polymers and particles in a dissolved or dispersed state, ensuring the integrity of antibodies or antigands, and enables efficient dispersion or aggregation upon temperature adjustment without inactivating the ligands.

Implementation Method 1

a polymer showing an upper critical solution temperature (hereinafter also referred to as 'UCST') in a state of an aqueous solution

Methodology Applied

Scientific EffectUpper critical solution temperature (UCST): Phase Change

Implementation Method 2

polyisopropyl acrylamide, showing a lower critical solution temperature (hereinafter referred to as 'LCST') in a state of an aqueous solution

Methodology Applied

Scientific EffectLower critical solution temperature (LCST): Phase Change

Data Source

PatentUS8105503B2Method of storing thermoresponsive polymer in state of aqueous solution

Publication Date: 2012.01.31 CHISSO CORP

AI summary

It is intended to provide an aqueous solution of a thermoresponsive polymer, which shows an upper critical solution temperature (UCST) and is capable of maintaining a dissolved state, even if it is stored for a long period of time at a temperature at which a ligand such as an antibody or an antigen is not inactivated. A UCST lowering agent is incorporated in a predetermined amount in an aqueous solution of a thermoresponsive polymer which shows a UCST in a state of containing water, thereby lowering the UCST of the aqueous solution to less than the storage temperature, and the resulting aqueous solution is stored.