# US 10,765,521 B2 · Biomimetic functional and regenerative cartilage implant

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- Number: US 10,765,521 B2
- Document ID: US10765521B2
- Status: Granted
- Kind: B2
- Application number: 16/332,253
- Filed: 2017-10-19
- Published: 2019-08-01
- Granted: 2020-09-08
- Earliest claimed: 2016-10-20
- Assignees: Technische Universiteit Eindhoven; RWTH Aachen
- Applicants: Technische Universiteit Eindhoven; RWTH Aachen
- Inventors: Corrinus Cornelis van Donkelaar; Keita Ito; Tim Bolle
- Web page: https://patentgrep.com/patent/US10765521B2

## CPC

- A61F 2/30756: {Cartilage endoprostheses (A61F2/3603 takes precedence)}
- A61L 27/50: Materials characterised by their function or physical properties {, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials}
- A61L 27/52: Hydrogels or hydrocolloids
- A61F 2002/30761: {Support means for artificial cartilage, e.g. cartilage defect covering membranes}
- A61F 2002/30766: {Scaffolds for cartilage ingrowth and regeneration}
- A61L 27/58: Materials at least partially resorbable by the body
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)

## Abstract

An artificial cartilage is provided whereby a fixed negative charged hydrogel has been infused within a restrictive swelling network, which limits and restricts the thickness of the artificial cartilage. At least 60% of the volume of the artificial cartilage is composed of the restricted and swollen hydrogel. The restrictive swelling network restricts the hydrogel to swell not more than 10% with respect to its maximum swelling capacity, i.e. a swelling capacity to swell 10-fold more is retained. The hydrogel within the restrictive swelling network has an equilibrium stiffness between 0.5 and 2 MPa to resist external loads applied to the top surface layer or the bottom surface layer of the artificial cartilage. The hydrogel has a fixed negative charge density of −0.17 to −0.23 mEg/ml and is capable of swelling between 2-15 times compared to the volume of the hydrogel without being restricted.

## Claims

### Claim 1

An artificial cartilage, comprising:
a fixed negative charged hydrogel infused within a restrictive swelling network,
wherein the restrictive swelling network is a spacer network of filaments with a top surface layer, a bottom surface layer, and some of the filaments crossing in a middle area layer between both the top and bottom surface layers limiting and restricting the maximum distance between both the top and bottom surface layers,
wherein the restrictive swelling network restricts the fixed negative charged hydrogel to swell not more than 10% with respect to the maximum swelling capacity of the fixed negative charged hydrogel without being constraint by the restrictive swelling network,
wherein the fixed negative charged hydrogel within the restrictive swelling network has an equilibrium stiffness between 0.5 and 2 MPa to resist external loads applied to the top surface layer or the bottom surface layer of the artificial cartilage.

### Claim 2 (depends on 1)

The artificial cartilage as set forth in claim 1, wherein at least 60% of the volume of the artificial cartilage is composed of the restricted and swollen fixed negative charged hydrogel.

### Claim 3 (depends on 1)

The artificial cartilage as set forth in claim 1, wherein the fixed negative charged hydrogel has a fixed negative charge density of −0.17 to −0.23 mEg/ml and is capable of swelling between 2-15 times compared to the volume of the hydrogel without being restricted.

### Claim 4 (depends on 1)

The artificial cartilage as set forth in claim 1, wherein the maximum distance between both the top and bottom surface layers is between 0.8-6 mm.

### Claim 5 (depends on 1)

The artificial cartilage as set forth in claim 1, wherein the middle area layer of the spacer network of filaments defines an interconnecting pile of filaments restricting the maximum distance between the top surface layer and the bottom surface layer, with a pile density of at least 10 filaments/cm2, wherein the maximum pile density is limited to ensure at least 60% of the volume of the artificial cartilage is composed of the restricted and swollen fixed negative charged hydrogel, with a pile angle between 45-90 degrees defined with reference to either the top or bottom surface layer, and with an elasticity of the spacer network of filaments between 100 kPa and 10 MPa defined in a load direction perpendicular to either the top or bottom surface layer.

### Claim 6 (depends on 1)

The artificial cartilage as set forth in claim 1, wherein the restrictive swelling network restricts the fixed negative charged hydrogel to swell not more than 5% with respect to the maximum swelling capacity of the fixed negative charged hydrogel without being constraint by the restrictive swelling network.