Polymer-Flavonoid Conjugates via Thiol Linkers for Stable Hydrogels
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Solution Overview
Problem
Flavonoids, such as EGCG, face challenges due to poor stability and limited oral bioavailability, making it difficult to utilize them effectively in biomedical applications, and existing methods struggle to synthesize stable polymer-flavonoid conjugates.
Innovation Solution
A polymer-flavonoid conjugate is created by linking a polymer, like hyaluronic acid, to a flavonoid via a thiol linker, allowing for high degrees of conjugation and stable attachment, which can be used to form hydrogels with improved bioavailability and bioactivity, and these hydrogels can be crosslinked using autoxidation or enzymatic methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flavonoids are chemically modified to enhance stability and bioavailability, then their stability and bioavailability improve, but the complexity of synthesis and purification increases
Solution Approach 1:
The patent uses thiol-containing compounds as intermediary agents to conjugate with flavonoids. The thiol group reacts selectively with the carbonyl group of flavonoids under basic conditions, forming stable thiohemiacetal linkages. This intermediary approach enables controlled modification while maintaining relatively simple synthesis procedures and avoiding complex purification steps.
2Reliability
If flavonoids are covalently modified with thiol-containing compounds, then stability improves, but autoxidation causes decomposition and reduces conjugation yield
Solution Approach 1:
The patent employs parameter changes by conducting the conjugation reaction under basic conditions (pH 8-10) where the thiolate anion is more nucleophilic and reacts faster with the carbonyl group. This kinetic acceleration occurs faster than the autoxidation rate, allowing high conjugation yields before significant decomposition occurs. The basic conditions also suppress autoxidation by reducing the formation of reactive oxygen species.
3Reliability
If hydrogen peroxide is generated during autoxidation to inhibit thiol oxidation, then thiol stability improves, but H2O2 oxidizes free thiol groups reducing conjugation efficiency
Solution Approach 1:
The patent applies preliminary action by pre-generating hydrogen peroxide in the reaction system before significant autoxidation of the thiol-flavonoid conjugate occurs. The H2O2 acts as a protective agent that suppresses further autoxidation and prevents decomposition. This preemptive approach maintains thiol stability while preserving conjugation efficiency by preventing subsequent oxidative damage to the product.
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 enhanced stability and bioavailability, enabling their use in biomedical applications, such as injectable systems for delivering therapeutic agents, with tunable mechanical properties and prolonged residence in the body.
Implementation Method 1
conjugating said flavonoid with said polymer via nucleophilic addition under basic conditions
Implementation Method 2
crosslinked using autoxidation or enzymatic methods
Implementation Method 3
crosslinked using autoxidation or enzymatic methods
Data Source
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AI summary
There is provided polymer-flavonoid conjugates. Flavonoid-grafted and flavonoid-terminated polymer conjugates are disclosed according to the invention. The linkage of flavonoids to the polymers has been achieved via thiol linkages. The inventive processes allow for making of the conjugates in high yield avoiding complex purification steps. The conjugates can be easily autoxidized to hydrogels with uses in many biomedical applications where a higher stability of the flavonoid is necessary. The hydrogels can be potentially used as viscosupplement, anti-adhesion film or dermal filler.