Reversible Biomolecular Labeling via Temperature-Sensitive Polymer
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Solution Overview
Problem
Current methods for removing magnetic labels from cells in immunomagnetic cell separation are often damaging, time-consuming, or require complex protocols, failing to maintain cells in a native state and compromising their viability and purity.
Innovation Solution
A method using low-avidity, high-affinity biomolecular interactions involving polymers and anti-polymer ligands for reversible labeling, where biological targets are bound to labels through a linking system and a second polymer is added to rapidly separate them under physiological conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to remove magnetic labels from cells, then the labels are removed from cells, but the cells suffer damage and viability is compromised
Solution Approach 1:
The patent employs a temperature-sensitive polymer (PNIPAM) conjugated to magnetic particles that undergoes a phase transition at a specific temperature (lower critical solution temperature). Below this temperature, the polymer is hydrophilic and maintains low affinity for cell membranes. Above this temperature, the polymer becomes hydrophobic and binds to cell membranes. This reversible parameter change allows gentle labeling and removal without damaging cells, resolving the contradiction between effective labeling and cell viability.
2Productivity
If conventional methods are used to remove magnetic labels from cells, then the labels are removed, but the process is time-consuming and complex
Solution Approach 1:
The temperature-sensitive PNIPAM polymer enables rapid label removal by simply changing the temperature parameter. When the temperature is lowered below the lower critical solution temperature, the polymer transitions from a hydrophobic bound state to a hydrophilic unbound state, causing automatic release of cells from magnetic particles. This eliminates the need for complex chemical treatments or extended incubation periods, achieving fast and simple label removal.
Solution Approach 2:
The temperature-sensitive polymer system is self-regulating: when cooled below its transition temperature, the polymer automatically transitions to a low-affinity state and releases cells without requiring additional reagents or manual intervention. The system performs the label removal function autonomously through the physical parameter change, reducing protocol complexity and time.
3Stability of the object's composition
If high-affinity binding is used to ensure strong label-cell attachment, then labeling stability is improved, but label removal becomes difficult and damaging
Solution Approach 1:
The patent uses a dynamic, temperature-responsive polymer system where the binding affinity between the magnetic particle coating and cell membrane is not fixed but can be reversibly adjusted. At physiological temperature (above LCST), the PNIPAM polymer exhibits high affinity for cell membranes, providing stable labeling. When temperature is reduced below LCST, the polymer's conformation and solubility change, dynamically reducing affinity and enabling gentle release. This dynamic control resolves the contradiction between stable binding and easy removal.
Solution Approach 2:
By changing the temperature parameter relative to the polymer's lower critical solution temperature, the system transitions between high-affinity binding (above LCST) and low-affinity release (below LCST) states. This parameter-driven control allows the same system to provide both stable labeling under physiological conditions and gentle, non-damaging removal under controlled temperature conditions.
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 efficient, rapid, and gentle removal of labels from cells, maintaining their viability and purity, and is applicable to various cell types and species, facilitating faster and more sophisticated cell separation and isolation.
Implementation Method 1
binding the biological target to the label through a linking system comprising a first polymer and a ligand that binds to the first polymer
Implementation Method 2
adding a second polymer to the sample to separate the biological target from the label
Implementation Method 3
Magnetic microparticles or nanoparticles are used to selectively target cells within a complex biological sample
Data Source
AI summary
This disclosure provides compositions and methods for a low-avidity, high-affinity and high-specificity biomolecular interaction that is rapidly reversible under physiological conditions. The methods comprise linking biological targets (such as molecules, proteins, DNA, cells, extracellular vesicles, etc.) with polymers and anti-polymer ligands and a way to reverse their binding using physiologically compatible polymeric compounds. The methods also comprise a way to combine different polymer/anti-polymer systems for orthogonal labeling. The compositions comprise labels including particles (fluorescent, magnetic, dense, etc.) conjugated to polymers or labels conjugated to anti-polymer antibodies. The compositions also comprise biomolecules (proteins, antibodies, DNA, etc.) conjugated to the polymers. These methods and compositions represent a major improvement to the state-of-the-art. They are particularly useful for separation and isolation of biological targets using particles, but have important application to other fields including fluorescent imaging.