Crosslinked Hyaluronan Chitosan Hydrogel Biostability
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Solution Overview
Problem
Hyaluronic acid (HA) is rapidly degraded in vivo, limiting its applications in biomedical uses due to its water-solubility and susceptibility to enzymes like hyaluronidase, and polyelectrolyte complexes with chitosan are not stable enough for effective use.
Innovation Solution
Covalently crosslinking hyaluronan with chitosan using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) at a pH of 7.2 or higher to prevent polyelectrolyte complex formation, allowing for the creation of stable and biocompatible hydrogels that can be used for drug delivery and tissue engineering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hyaluronan is used in biomedical applications, then it provides good biocompatibility and non-immunogenicity, but it is rapidly degraded by oxidation and enzymes like hyaluronidase due to its water-solubility
Solution Approach 1:
The patent combines hyaluronan with chitosan to form a composite hydrogel material. This composite structure provides the biocompatibility of hyaluronan while the crosslinked network structure confers stability and resistance to enzymatic degradation, resolving the contradiction between biocompatibility and in vivo stability.
Solution Approach 2:
The patent changes the physical and chemical parameters of hyaluronan by crosslinking it with chitosan using EDC at controlled pH levels (7.2-7.8). This transformation converts the water-soluble, rapidly degradable hyaluronan into a stable hydrogel network that maintains biocompatibility while achieving prolonged duration of action in vivo.
2Stability of the object's composition
If polyelectrolyte complexes of hyaluronan and chitosan are formed, then they provide enhanced stability, but they are cloudy solids with very limited capacity to adsorb water and are only moderately stable in normal pH range
Solution Approach 1:
The patent controls the pH parameter during complex formation to remain between 7.2-7.8, preventing precipitation and maintaining a clear, water-soluble hydrogel. This pH control allows the formation of stable hyaluronan-chitosan complexes that retain high water adsorption capacity, unlike traditional polyelectrolyte complexes that precipitate at lower pH.
Solution Approach 2:
The patent uses EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) as a chemical intermediary to facilitate covalent bonding between hyaluronan and chitosan. This intermediary enables the formation of stable crosslinked hydrogels that maintain water solubility and high water adsorption capacity while achieving enhanced compositional stability.
3Duration of action of stationary object
If covalent crosslinking is performed to improve stability, then biostability and resistance to enzymatic degradation are achieved, but the process requires precise pH control and additional reagents like EDC
Solution Approach 1:
The patent optimizes the pH parameter to the range of 7.2-7.8, which is slightly above physiological pH. This specific parameter setting maximizes the efficiency of EDC-mediated crosslinking while ensuring biocompatibility and preventing polyelectrolyte complex formation, achieving biostability with a relatively simple controlled process.
Solution Approach 2:
The patent employs EDC as a water-soluble carbodiimide intermediary that enables efficient covalent crosslinking under mild, physiologically compatible conditions. This intermediary simplifies the crosslinking process by allowing it to proceed in aqueous solution at controlled pH without requiring complex equipment or extreme conditions, achieving biostability through a manageable process.
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 crosslinked HA/chitosan materials are biostable, biocompatible, and can be used for various biomedical applications, including drug delivery and tissue engineering, with improved mechanical strength and resistance to enzymatic degradation.
Implementation Method 1
In aqueous solution, the carboxyl groups of hyaluronan can be activated, followed by nucleophilic addition by amino groups of chitosanic polymers to form an intermolecular amide linkage
Implementation Method 2
covalently crosslinked in the presence of agents such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)
Implementation Method 3
by adjusting the pH of solutions of hyaluronan and glycol chitosan so that the pH of the mixed solution is 7.2 or higher, formation of the complex between hyaluronan and glycol chitosan can be prevented
Data Source
AI summary
Materials and methods related to crosslinking hyaluronan and chitosan are described herein. Also described are products of the described methods.