Crosslinked Chitosan Hydrogel Beads for Injectable Biointegration
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Solution Overview
Problem
Existing injectable beads made of bioresorbable polymers face issues with tolerance, biointegration, and stability, particularly due to non-spherical shapes and irregular surfaces, leading to foreign body responses and granulomas, and lack of covalent bonding, which affects their integrity and ease of administration.
Innovation Solution
Development of spherical hydrogel beads composed of crosslinked carboxyalkyl chitosan with controlled degrees of acetylation and substitution, covalently bonded and optionally co-crosslinked with other polymers, ensuring biocompatibility, stability, and ease of administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If non-spherical hydrogel beads are used, then ease of manufacture is improved, but foreign body response and granuloma formation increase
Solution Approach 1:
The patent applies spheroidality by forming hydrogel beads with a spherical shape through controlled polymerization and crosslinking processes. The spherical morphology is achieved by incorporating spherical templates or using diffusion-controlled polymerization that naturally forms spherical structures, thereby reducing foreign body responses and granuloma formation while maintaining manufacturability.
2Ease of manufacture
If non-covalent bonds are used for bead formation, then ease of manufacture is improved, but bead integrity and stability deteriorate
Solution Approach 1:
The patent employs composite materials by combining multiple polymer components with different functional properties. The hydrogel beads consist of a composite polymer matrix where some polymers provide structural integrity through covalent bonding while others contribute to manufacturability and biocompatibility, achieving both stability and ease of manufacture simultaneously.
Solution Approach 2:
The patent applies parameter changes by controlling the degree of crosslinking, polymer molecular weight, and composition ratios to optimize both bead integrity and manufacturability. By adjusting crosslinking density and polymer parameters, the beads achieve sufficient stability while remaining easy to manufacture through standard techniques.
3Ease of manufacture
If irregular surface morphology is used, then ease of manufacture is improved, but biointegration and tolerance deteriorate
Solution Approach 1:
The patent applies spheroidality by producing beads with smooth spherical surfaces through controlled polymerization. The spherical shape with uniform surface morphology is achieved by using spherical templates or diffusion-controlled growth, thereby improving biointegration and tolerance while maintaining ease of manufacture.
Solution Approach 2:
The patent applies parameter changes by controlling polymerization conditions, temperature, pH, and monomer ratios to achieve smooth spherical surfaces. By optimizing these parameters, the beads exhibit regular surface morphology that enhances biointegration while remaining easy to manufacture.
4Stability of the object's composition
If large injection force is required, then bead stability is improved, but ease of administration deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting hydrogel viscosity, crosslinking density, and bead size to achieve optimal balance between stability and injectability. By controlling these parameters, the beads maintain sufficient stability while requiring minimal injection force for easy administration through standard needles.
Solution Approach 2:
The patent applies dynamics by designing hydrogels with viscoelastic properties that allow the beads to flow through needles during injection then maintain their shape in the target tissue. The dynamic rheological properties enable easy administration while preserving bead stability after injection.
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 beads provide improved tolerance, stability, and biomechanical properties, allowing for safe and effective volumisation and drug delivery with reduced immunoreactivity and foreign body responses, suitable for various medical applications.
Implementation Method 1
a carboxyalkyl chitosan being crosslinked by covalent bonds between the carboxyalkyl chitosan chains
Implementation Method 2
beads in a human being or an animal, comprising or consisting of a hydrogel matrix
Data Source
AI summary
The invention relates to beads and a composition comprising an aqueous phase comprising a plurality of beads, the beads comprising or consisting in a hydrogel matrix comprising at least one carboxyalkyl chitosan having glucosamine units, N-acetyl-glucosamine units and glucosamine units substituted with a carboxyalkyl group, the carboxyalkyl chitosan being crosslinked by covalent bonds between the carboxyalkyl chitosan chains and/or co-crosslinked by covalent bonds with one or more other polymers.The invention also relates to processes for their preparation and applications thereof.