Cellulose-based hydrogels and methods of making thereof
First Claim
1. A re-wet cellulose hydrogel wherein the hydrogel comprises a cellulose content of about 55% by weight and one or more properties selected from the group consisting of:
- a tensile strength of from about 1000 kPa to about 5000 kPa;
a tear strength of from about 3.0 N/mm to about 12 N/mm;
a strain to failure of from about 20% to about 40%;
a suture retention strength of from about 1.0 N/mm to about 7.0 N/mm;
a transparency that exceeds 85% at 550 nm at 100 microns thickness;
Young'"'"'s modulus of from about 4000 kPa to about 15000 kPa; and
a puncture resistance of from about 3 MPa to about 5 MPa,wherein the hydrogel is in the shape of a contact lens, andwherein the cellulose is from a source selected from the group consisting of plant, wood pulp, cotton pulp, microbial, and combinations thereof.
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Abstract
The present invention provides cellulose hydrogels having one or more of the following properties: high water content, high transparency, high permeability, high biocompatibility, high tensile strength and an optimal thickness. The present invention further provides a process for preparing a cellulose hydrogel comprising: (i) contacting cellulose with a solvent to activate the cellulose; (ii) optionally removing the solvent from the activated cellulose; (iii) substantially dissolving the activated cellulose to form a solution; (iv) allowing the solution to gel; and optionally (v) drying the gel and rehydrating the gel. The cellulose hydrogel can have many uses, including uses as contact lenses.
29 Citations
20 Claims
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1. A re-wet cellulose hydrogel wherein the hydrogel comprises a cellulose content of about 55% by weight and one or more properties selected from the group consisting of:
- a tensile strength of from about 1000 kPa to about 5000 kPa;
a tear strength of from about 3.0 N/mm to about 12 N/mm;
a strain to failure of from about 20% to about 40%;
a suture retention strength of from about 1.0 N/mm to about 7.0 N/mm;
a transparency that exceeds 85% at 550 nm at 100 microns thickness;
Young'"'"'s modulus of from about 4000 kPa to about 15000 kPa; and
a puncture resistance of from about 3 MPa to about 5 MPa,wherein the hydrogel is in the shape of a contact lens, and wherein the cellulose is from a source selected from the group consisting of plant, wood pulp, cotton pulp, microbial, and combinations thereof. - View Dependent Claims (2, 3, 5, 6, 7, 8, 10)
- a tensile strength of from about 1000 kPa to about 5000 kPa;
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4. A re-wet cellulose hydrogel wherein the hydrogel comprises one or more properties selected from the group consisting of:
- a cellulose content of from about 40% to about 65% by weight;
a tensile strength of from about 1000 kPa to about 5000 kPa;
a tear strength of from about 3.0 N/mm to about 12 N/mm;
a strain to failure of from about 20% to about 40%;
a suture retention strength of from about 1.0 N/mm to about 7.0 N/mm;
a transparency that exceeds 85% at 550 nm at 100 microns thickness;
Young'"'"'s modulus of from about 4000 kPa to about 15000 kPa; and
a puncture resistance of from about 3 MPa to about 5 MPa, the hydrogel further comprising cellulose starting material having a density of about 0.20-0.40 g/cm3 and a moisture content of about 2-6% by weight,wherein the hydrogel is in the shape of a contact lens.
- a cellulose content of from about 40% to about 65% by weight;
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9. A re-wet cellulose hydrogel wherein the hydrogel comprises one or more properties selected from the group consisting of:
- a cellulose content of from about 40% to about 65% by weight;
a tensile strength of from about 1000 kPa to about 5000 kPa;
a tear strength of from about 3.0 N/mm to about 12 N/mm;
a strain to failure of from about 20% to about 40%;
a suture retention strength of from about 1.0 N/mm to about 7.0 N/mm;
a transparency that exceeds 85% at 550 nm at 100 microns thickness;
Young'"'"'s modulus of from about 4000 kPa to about 15000 kPa; and
a puncture resistance of from about 3 MPa to about 5 MPa, the hydrogel,wherein the hydrogel is a composite comprising microcrystalline cellulose and bacterial cellulose.
- a cellulose content of from about 40% to about 65% by weight;
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11. A process for preparing a cellulose hydrogel comprising:
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(i) contacting cellulose with a solvent to activate the cellulose, the cellulose comprising cellulose starting material having a density of about 0.20-0.40 g/cm3 and a moisture content of about 2-6% by weight; (ii) optionally removing the solvent from the activated cellulose; (iii) substantially dissolving the activated cellulose to form a solution; (iv) allowing the solution to gel; and optionally (v) drying the gel and rehydrating the gel. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A wet cellulose hydrogel wherein the hydrogel comprises one or more properties selected from the group consisting of:
- a cellulose content of from about 2% to about 9% by weight;
a tensile strength in the range of from about 50 kPa to about 600 kPa;
a tear strength of from about 0.10 N/mm to about 0.60 N/mm;
a strain to failure of from about 40% to about 80%;
a suture retention strength of from about 0.05 N/mm to about 0.30 N/mm;
a transparency that exceeds 85% at 550 nm;
Young'"'"'s modulus of from about 100 kPa to about 700 kPa; and
a puncture resistance of from about 50 kPa to about 300 kPa, wherein the hydrogel is a composite comprising microcrystalline cellulose and bacterial cellulose.
- a cellulose content of from about 2% to about 9% by weight;
Specification