Dextran Hydrogel Carbonyl Crosslinking Biocompatibility
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Solution Overview
Problem
Developing biodegradable dextran-based hydrogels with efficient crosslinking methods remains challenging due to the difficulty in introducing polymerizable bonds for effective crosslinking, and existing hydrogels face issues with biocompatibility and controlled release of therapeutic agents.
Innovation Solution
The use of polysaccharides with specific substituted hydroxyl groups, such as dextran, combined with poly(ethylene glycol) diacrylate, to form crosslinked hydrogels that enable efficient protein, oligonucleotide, or pharmaceutical agent delivery, with a focus on high polysaccharide content and controlled biodegradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vinyl groups are incorporated via acrylates to enable photocrosslinking, then crosslinking efficiency is improved, but biocompatibility deteriorates due to residual monomers and harsh crosslinking conditions
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking system by using carbonyl groups (aldehydes or ketones) instead of vinyl/acrylate groups. This allows crosslinking to proceed under milder conditions (pH 4-8, ambient temperature) without requiring photoinitiators or UV irradiation, thereby improving biocompatibility while maintaining crosslinking efficiency. The carbonyl-based crosslinking mechanism avoids the formation of harmful residual monomers associated with acrylate systems.
Solution Approach 2:
The patent employs naturally occurring carbonyl groups on dextran molecules as the crosslinking functionality, eliminating the need for synthetic acrylate monomers. These carbonyl groups are inherently present in the polysaccharide structure and can be directly utilized for crosslinking without requiring additional chemical modifications or disposable reagents, reducing the overall chemical burden on the biological system.
2Object-affected harmful factors
If high polysaccharide content is used to improve biocompatibility, then biodegradability is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent creates a composite crosslinking structure where carbonyl groups from polysaccharide chains form intermolecular crosslinks through hydrate formation or acetal/ketal linkages. This composite approach allows the hydrogel to maintain high polysaccharide content (improving biocompatibility and biodegradability) while the crosslinked network structure provides the necessary mechanical strength. The crosslinks act as reinforcing elements within the polysaccharide matrix.
Solution Approach 2:
The patent applies crosslinking locally at specific functional groups (carbonyl groups) on the polysaccharide chains rather than requiring high overall polymer concentration. This localized crosslinking strategy allows the bulk material to maintain high polysaccharide content for biocompatibility while the crosslinked regions provide mechanical reinforcement, effectively decoupling these two properties.
3Stability of the object's composition
If chemical crosslinking agents are used to improve mechanical integrity, then hydrogel stability is improved, but controlled release capability deteriorates due to non-biodegradable residues
Solution Approach 1:
The patent employs self-crosslinking chemistry where carbonyl groups on the polysaccharide chains themselves serve as the crosslinking functionality. The carbonyl groups form crosslinks through natural chemical reactions (hydrate formation, acetal/ketal linkages) without requiring external chemical crosslinking agents. This self-service approach ensures that the hydrogel network is composed entirely of biodegradable polysaccharide components, enabling complete degradation and controlled release of therapeutic agents without leaving non-biodegradable residues.
Solution Approach 2:
The patent uses water molecules as intermediaries in the crosslinking process, where carbonyl groups form hydrates with water that then link to other carbonyl groups or hydroxyl groups on adjacent polysaccharide chains. This water-mediated crosslinking mechanism allows for reversible, dynamic crosslinks that can break and reform, facilitating controlled release of encapsulated agents while maintaining hydrogel stability. The use of water as an intermediary ensures biodegradability since water is readily available and does not leave harmful residues.
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 resulting hydrogels exhibit improved biocompatibility, controlled release profiles, and enhanced biodegradability, facilitating the delivery of therapeutic agents while maintaining mechanical integrity and vascular regeneration.
Implementation Method 1
crosslinking of the polysaccharide chains through hydrate formation and acetal and/or ketal linkages
Implementation Method 2
crosslinking of the polysaccharide chains through hydrate formation and acetal and/or ketal linkages
Implementation Method 3
crosslinking of the polysaccharide chains through hydrate formation and acetal and/or ketal linkages
Implementation Method 4
dextran can be biodegraded by dextranase, which exists in mammalian (including human) tissues
Data Source
AI summary
Modified polysaccharides and crosslinked modified polysaccharide compositions are described. Methods of using the crosslinked modified polysaccharide compositions to deliver proteins, oligonucleotides, or pharmaceutical agents are also disclosed.