Composite gels and methods of use thereof
Inventors
Horkay, Ferenc • Basser, Peter Joel
Assignees
US Department of Health and Human Services
Publication Number
US-12083246-B2
Publication Date
2024-09-10
Expiration Date
2040-02-06
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Abstract
A self-reinforcing composite gel includes a solvent, and a plurality of swellable crosslinked polymer particles dispersed in a crosslinked polymer matrix, wherein the crosslinked polymer matrix and the plurality of swellable crosslinked polymer particles are immersed in the solvent, wherein the swellable crosslinked polymer particles absorb more solvent at equilibrium than the matrix polymer, and wherein the plurality of swellable crosslinked polymer particles swell in the solvent and are present in an amount sufficient to maintain or increase the elastic modulus and/or load-bearing ability of the self-reinforcing composite gel, i.e., compared to that of the crosslinked matrix polymer alone, upon swelling in the solvent.
Core Innovation
The invention relates to self-reinforcing composite gels comprising a solvent and a plurality of swellable crosslinked polymer particles dispersed in a crosslinked polymer matrix, both immersed in the solvent. The swellable crosslinked polymer particles absorb more solvent at equilibrium than the matrix polymer and are present in an amount sufficient to maintain or increase the elastic modulus and/or load-bearing ability of the composite gel upon swelling. This composite exhibits behavior opposite to its individual components where typically, swelling causes mechanical strength to decrease, but in this invention, the elastic modulus remains the same or increases upon swelling.
The problem addressed by the invention is that conventional gel materials, including hydrogels, typically lose mechanical strength as they swell, which limits their use in biological applications such as cartilage repair, as well as non-biological applications including engineering and construction sealing and repair. There is a need for novel materials that have functional properties similar to human collagen-based cartilage, particularly preserving or enhancing load-bearing ability despite swelling.
Claims Coverage
The patent includes one independent claim directed to a self-reinforcing composite gel and one independent claim directed to a method of making such a gel. Each independent claim focuses on different inventive features.
Composition of self-reinforcing composite gel with specific polymers and swelling behavior
The composite gel comprises water as solvent, a plurality of swellable crosslinked microgel polymer particles comprising poly(acrylic acid) sized 5 to 10 μm, dispersed in a crosslinked polymer matrix comprising poly(vinyl alcohol). The swellable microgel particles absorb more solvent at equilibrium than the matrix polymer and are present in an amount sufficient to maintain or increase the elastic modulus and/or load-bearing ability upon swelling. The gel is a hydrogel with the matrix and particles immersed in the solvent.
Method for making the self-reinforcing composite gel with controlled swelling suppression and crosslinking
The method includes combining a crosslinkable matrix-forming polymer, a plurality of swellable crosslinked microgel polyelectrolyte polymer particles, an acid, base, or salt to suppress particle swelling, a crosslinker, optionally a buffer and a solvent to form a first solution. The matrix-forming polymer is crosslinked in the solution forming a crosslinked matrix polymer. Then the acid, base or salt and uncrosslinked polymer are removed providing a second solution with dispersed swellable particles. Finally, freeze-thawing the second solution produces the self-reinforcing composite gel with particles dispersed in the crosslinked matrix, the particles absorb more solvent at equilibrium than the matrix polymer, and are sufficient to increase the elastic modulus and/or load-bearing ability upon swelling.
The claims cover a self-reinforcing composite hydrogel composition featuring a crosslinked poly(vinyl alcohol) matrix with dispersed poly(acrylic acid) microgel particles of defined size and swelling properties, and a method of manufacture involving controlled swelling suppression during crosslinking and freeze-thaw processing to produce the composite gel with enhanced elastic modulus and load-bearing ability upon swelling.
Stated Advantages
The self-reinforcing composite gels maintain or increase their elastic modulus and load-bearing ability upon swelling, contrary to typical gels whose mechanical strength decreases with swelling.
The composite gels mimic the mechanical behavior and prestressed structure of human cartilage extracellular matrix, providing a biomimetic model system.
The gels allow tailoring of mechanical and swelling properties by adjusting polymer composition, crosslink density, and particle size.
The composite gels' prestress mechanism enables enhanced load-bearing capacity analogous to reinforced biological tissues and engineered structures.
The materials can be systematically studied to inform tissue engineering strategies and cartilage repair applications.
Documented Applications
Tissue repair including cartilage repair, intervertebral disc repair, and breast implantation.
Tissue engineering or regenerative medicine by providing a population of cells in the composite hydrogel.
Slow drug release by administering the composite gel comprising a drug.
pH-dependent drug release where swellable particles remain unswollen in the stomach and swell in the intestine to release drug.
Sealing, repairing, or maintaining engineered or constructed parts including tunnels, drainage systems, damaged sewer pipes, oil pipes, underwater sealing, swimming pools, and repair of concrete joints.
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