Reversible Hydrogels via Segmented Cross-Linking
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Solution Overview
Problem
Current hydrogels face limitations in mechanical strength, biodegradability, and reversibility, making them unsuitable for biomedical applications, particularly in terms of processing and administration, due to their irreversible chemical cross-linking and limited tunability of mechanical properties.
Innovation Solution
Development of hydrogels with a polymeric water gellant comprising a polymer backbone covalently linked to hydrogen bonding units via a hydrophobic linker, using urea or amide moieties, allowing for reversible supramolecular interactions that enable easy processing and biodegradability without toxic metal-based catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chemical cross-linking is used to form hydrogels, then mechanical strength is improved, but reversibility and biodegradability are lost
Solution Approach 1:
The patent divides the cross-linking mechanism into two distinct components: covalent bonds for mechanical strength and reversible supramolecular interactions (hydrogen bonds, ionic interactions, metal coordination) for adaptability. This segmentation allows the hydrogel to simultaneously achieve both strong mechanical properties and reversible behavior, resolving the contradiction between strength and reversibility
Solution Approach 2:
The patent creates composite hydrogel structures combining covalently cross-linked polymer networks with supramolecular assemblies. The covalent framework provides mechanical strength while the supramolecular components enable reversibility and stimulus-responsiveness, effectively resolving the contradiction through material composition
2Strength
If chemical cross-linking is used to form hydrogels, then mechanical strength is improved, but biodegradability is lost
Solution Approach 1:
The patent segments the cross-linking function into covalent bonds for strength and biodegradable supramolecular interactions for controlled degradation. The supramolecular cross-links can be designed to break down under specific physiological conditions, enabling biodegradability while maintaining mechanical integrity through the covalent network
Solution Approach 2:
The patent employs biodegradable polymers with controllable degradation rates and designs supramolecular interactions with specific stability parameters. By adjusting polymer composition, molecular weight, and supramolecular bond strength, the hydrogel achieves both adequate mechanical strength and controlled biodegradability under physiological conditions
3Strength
If irreversible chemical cross-linking is used, then mechanical strength is improved, but processing ease is worsened
Solution Approach 1:
The patent introduces dynamic reversibility to the cross-linking system through supramolecular interactions that can form and break under different conditions. This allows the hydrogel to be processed in a reversible state (easy manufacturing) and then locked into a stable strong state (final product), resolving the contradiction between processing ease and mechanical strength
4Reliability
If natural polymers are used for hydrogels, then biocompatibility is improved, but mechanical strength is reduced
Solution Approach 1:
The patent creates composite systems combining natural biocompatible polymers with synthetic cross-linking mechanisms. The natural polymer matrix provides biocompatibility while the controlled supramolecular and covalent cross-linking provides enhanced mechanical strength, resolving the contradiction through composite material design
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 easy processing and administration, while avoiding the use of toxic catalysts, thus enhancing their suitability for biomedical applications.
Implementation Method 1
comprise water gellants comprising hydrophilic polymers to which several 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
Implementation Method 3
The hydrogels are formed because of phase separation of the hard hydrophobic polyester block
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.