Hydrogel nanocomposites for intraocular lens applicatons
Inventors
Assignees
US Department of Veterans Affairs • Washington University in St Louis WUSTL
Publication Number
US-8877227-B2
Publication Date
2014-11-04
Expiration Date
2023-11-13
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
The present invention relates to reversible hydrogel systems. Particularly, the hydrogel of the present invention is made up of copolymers that can be a hydrogel when in an oxidized state and can be a solution when in a reduced state. A solution of the copolymer can be oxidized to form a hydrogel; and the hydrogel can be reduced to form a solution of the copolymer. Reversible nanogels can also be formed from a dilute solution of the copolymers. The hydrogel is formed with nanoparticles embedded therein to form a nanocomposite whose refractive index and modulus can be controlled by varying the amounts of nanoparticles and the polymer concentration of the hydrogel, respectively.
Core Innovation
The present invention relates to reversible hydrogel systems composed of copolymers that can switch between a hydrogel state when oxidized and a solution state when reduced. The copolymer solution can be oxidized to form a hydrogel; conversely, the hydrogel can be chemically reduced to yield a soluble polymer solution. This reversible behavior can also be triggered by photo-addition chemistry or mechanical shear forces, enabling formation of hydrogels and their dissolution accordingly.
The hydrogel system incorporates nanoparticles embedded within the polymer network to form nanocomposites. These nanocomposites enable control over both refractive index and mechanical modulus independently by altering the nanoparticle concentration and polymer concentration, respectively. This addresses the difficulty in controlling refractive index without affecting modulus in conventional hydrogels.
The problem being solved arises primarily in context of intraocular lenses (IOLs) used in cataract surgery. Existing IOLs usually have fixed focal lengths and lack accommodation capability, causing patients to rely on reading glasses post-surgery. Injectable, in situ forming gels offer minimally invasive application and conform to the capsular bag, but prior injectable hydrogels suffer from toxicity due to residual monomers, exothermic polymerization, irreversible gelation, and poor control of mechanical and optical properties. There is a need for an accommodative IOL material that mimics natural lens properties, has reversible gelation, optical clarity, and control over refractive index and modulus independently.
Claims Coverage
The patent discloses one independent claim centered on the structure and composition of an accommodating intraocular lens formed by in situ gelation of a hydrogel nanocomposite. The inventive features encompass the reversible hydrogel composition, nanoparticle characteristics, and controllable optical and mechanical properties.
Accommodating intraocular lens with reversible hydrogel nanocomposite
The lens is formed by in situ gelation of a hydrogel nanocomposite comprising a reversible hydrogel with nanoparticles dispersed therein, where the nanoparticles have diameters less than 150 nm.
Nanoparticles with specific composition and optical properties
The nanoparticles embedded in the hydrogel nanocomposite are selected from nanogel, protein, silica, gold, silver, TiO2, transition metals, ceramic, or their combinations and do not disperse or scatter visible light, preferably having diameters between 3 and 20 nm.
Hydrogel reversibly switches between gel and solution states
The hydrogel comprises a copolymer that forms a hydrogel when oxidized and exists as a solution when reduced, wherein reduction is achieved by adding a reducing agent and oxidation reforms the hydrogel via atmospheric oxygen, light, or riboflavin.
Copolymer composition with reversible crosslinkers
The copolymer is produced by polymerizing monomers (e.g., acrylamide, N-ornithine acrylamide, polyethyleneglycol acrylates, N-vinyl pyrolidone, N-phenylacrylamide, and others) with reversible crosslinkers, including disulfide linkers like N,N'-bis(acryloyl)cystamine, or photochemically reversible groups such as stilbene, azo, or cinnamoyl derivatives.
Independent control of refractive index and modulus
The hydrogel nanocomposite's refractive index can be increased by raising nanoparticle concentration, while the modulus can be controlled separately by adjusting the copolymer concentration within the hydrogel matrix, enabling tuning of optical and mechanical properties simultaneously.
The claims cover an accommodating intraocular lens composed of a reversible hydrogel nanocomposite with embedded nanoparticles less than 150 nm that allow independent tuning of refractive index and mechanical modulus, providing reversible sol-gel behavior through oxidation and reduction of disulfide or photochemical crosslinks, and establishing precise composition and structure of copolymers and nanoparticles suitable for intraocular applications.
Stated Advantages
Reversible hydrogel system enables in situ gelation and liquefaction without exothermic reactions or toxic residual monomers.
Control over refractive index and modulus independently by varying nanoparticle and polymer concentrations respectively.
Nanoparticles are chosen to be non-light scattering, maintaining optical clarity essential for intraocular lenses.
Injectable formulation allows minimally invasive delivery and conforming to the shape of the lens capsular bag.
The system enables restoration of accommodation capabilities lost in standard intraocular lenses.
Documented Applications
Injectable intraocular lens materials for cataract surgery to restore accommodation and eliminate need for reading glasses.
Vitreous substitutes by in situ gel formation within vitreous cavity of the eye.
Topical medicaments using reversible hydrogel formulations.
Interested in licensing this patent?