Reversible Hydrogels via Hydrophobic Linker Cross-Linking
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Solution Overview
Problem
Current hydrogel materials face limitations in reversibility, mechanical strength, and biodegradability, particularly in biomedical applications, where they often require toxic catalysts and have restricted tunability and processing difficulties.
Innovation Solution
Development of hydrogels with a water gellant comprising a hydrophilic polymer backbone to which simple hydrogen bonding units are covalently attached via a hydrophobic linker, allowing for reversible supramolecular interactions and biodegradability without toxic metal-based catalysts, enabling easy processing and administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chemical cross-linking is used to obtain hydrogels, then mechanical strength is improved, but reversibility and biodegradability are lost
Solution Approach 1:
The patent changes the chemical nature of cross-links from permanent covalent bonds to reversible non-covalent interactions (hydrogen bonds, ionic interactions, hydrophobic effects). This parameter change allows the hydrogel to maintain mechanical strength while gaining reversibility and biodegradability, as the cross-links can dynamically break and reform without permanent chemical modification
Solution Approach 2:
The patent employs a composite cross-linking strategy combining multiple non-covalent interaction types (hydrogen bonding, ionic interactions, hydrophobic effects) to achieve mechanical properties comparable to chemically cross-linked gels while maintaining reversibility. The synergistic combination of these weak interactions creates a robust yet dynamic network
2Reliability
If natural polymers are used for hydrogels, then biocompatibility is improved, but mechanical strength is reduced
Solution Approach 1:
The patent creates composite hydrogel systems combining natural polymer backbones with synthetic cross-linking motifs or hybrid natural-synthetic polymer combinations. This allows the natural polymer to provide biocompatibility while the synthetic components or hybrid structure enhance mechanical strength through additional interaction sites and network rigidity
Solution Approach 2:
The patent introduces regions of enhanced mechanical properties within the natural polymer matrix by incorporating cross-linkable functional groups at specific locations or creating phase-separated domains with different mechanical characteristics, allowing local reinforcement without compromising overall biocompatibility
3Stability of the object's composition
If hydrophobic blocks are increased to improve gelling behavior, then gelling is enhanced, but elasticity and mechanical property range are limited
Solution Approach 1:
The patent adjusts the hydrophobic content and distribution within the polymer structure to optimize the balance between gelling ability and mechanical versatility. By controlling the amount, length, and positioning of hydrophobic segments, the hydrogel can achieve stable gelling while maintaining a wide range of mechanical properties including elasticity
Solution Approach 2:
The patent introduces dynamic and reversible cross-linking mechanisms that allow the hydrogel network to adapt its mechanical properties in response to environmental conditions. This dynamic character enables the material to exhibit both stable gelling behavior and tunable elasticity, as the cross-links can reversibly form and break under different stress conditions
4Stability of the object's composition
If acrylic or methacrylic macromonomers are used for cross-linking, then hydrogel formation is achieved, but toxicity and processing difficulty increase
Solution Approach 1:
The patent removes toxic components (acrylic/methacrylic monomers and their initiators) from the hydrogel system and replaces them with non-toxic alternatives that achieve hydrogel formation through non-covalent cross-linking. This extraction of harmful substances is achieved by using polymers with inherent cross-linking capabilities through hydrogen bonding or ionic interactions, eliminating the need for toxic chemical cross-linkers
Solution Approach 2:
The patent employs biodegradable polymer components that can be safely metabolized or excreted, replacing persistent toxic cross-linking agents. The use of naturally occurring or biocompatible polymers with temporary cross-linking structures that degrade over time provides a safe alternative to permanent toxic cross-links
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
The hydrogels exhibit improved mechanical performance, reversibility, and biodegradability, facilitating their use in biomedical applications with enhanced processing and administration capabilities.
Implementation Method 1
hydrogen bonding units are covalently attached via an apolar motif so that they are cross-linked in a reversible supramolecular way by hydrogen bonds
Implementation Method 2
hydrogels are three-dimensional networks of polymer chains with a high content of absorbed water molecules
Data Source
AI summary
The present invention relates to improved hydrogel materials using water gellants that are comprised of polymer backbones P to which hydrogen bonding 4H-units are covalently attached via a hydrophobic linker L. Optionally, the hydrogel contains additional ingredients or additives. These new reversible hydrogels can easily be fine-tuned in their mechanical performance and function and are especially suitable for biomedical applications.