# US 7,674,477 B1 · Bone and tissue scaffolding for delivery of therapeutic agents

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- Number: US 7,674,477 B1
- Document ID: US7674477B1
- Status: Granted
- Kind: B1
- Application number: 11/325,530
- Filed: 2006-01-05
- Granted: 2010-03-09
- Earliest claimed: 2003-11-06
- Assignees: University of Notre Dame du Lac
- Inventors: Steven R. Schmid; Glen L. Niebur; Dale R. Sumner
- Web page: https://patentgrep.com/patent/US7674477B1

## CPC

- A61F 2/28: Bones
- A61L 27/56: Porous materials, {e.g. foams or sponges}
- A61F 2/30965: {Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping}
- A61F 2002/30006: {differing in density or specific weight}
- A61F 2002/30011: {differing in porosity}
- A61F 2002/30062: {(bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive}
- A61F 2002/30064: {Coating or prosthesis-covering structure made of biodegradable material}
- A61F 2002/30087: {piezoelectric}
- A61F 2002/30092: {using shape memory or superelastic materials, e.g. nitinol}
- A61F 2002/30677: {Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body}
- A61F 2002/3092: {having an open-celled or open-pored structure}
- A61F 2002/30925: {etched}
- A61F 2002/30948: {using computerized tomography, i.e. CT scans}
- A61F 2002/30957: {using a positive or a negative model, e.g. moulds}
- A61F 2002/30967: {Diffusion bonding}
- A61F 2002/3097: {using laser}
- A61F 2002/30971: {Laminates, i.e. layered products}
- A61F 2002/30978: {using electrical discharge machining [EDM]}
- A61F 2210/0004: bioabsorbable
- A61F 2210/0014: using shape memory or superelastic materials, e.g. nitinol
- A61F 2250/0015: differing in density or specific weight
- A61F 2250/0023: differing in porosity
- A61F 2310/00017: Iron- or Fe-based alloys, e.g. stainless steel
- A61F 2310/00023: Titanium or titanium-based alloys, e.g. Ti-Ni alloys
- A61F 2310/00029: Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
- A61F 2310/00041: Magnesium or Mg-based alloys
- A61F 2310/00059: Chromium or Cr-based alloys
- A61F 2310/00131: Tantalum or Ta-based alloys
- A61F 2310/00203: containing alumina or aluminium oxide
- A61F 2310/00239: containing zirconia or zirconium oxide ZrO2
- A61F 2310/00293: containing a phosphorus-containing compound, e.g. apatite
- A61F 2310/00395: Coating or prosthesis-covering structure made of metals or of alloys
- A61F 2310/0058: Coating made of diamond or of diamond-like carbon DLC
- A61F 2310/00592: Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds
- A61F 2310/00604: Coating made of aluminium oxide or hydroxides
- A61F 2310/00796: Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
- A61F 2310/0097: Coating or prosthesis-covering structure made of pharmaceutical products, e.g. antibiotics
- B33Y 70/00: Materials specially adapted for additive manufacturing
- B33Y 80/00: Products made by additive manufacturing
- 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)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING

## Abstract

The present invention provides a bone in-growth surface for implants which has a structure for delivering therapeutic agents to surrounding bone and tissue. The bone in-growth surface may comprise scaffolding and a controlled-permeability layer which contains the therapeutic agents in a variety of reservoirs. The porosity of the scaffolding may be controllable from zero porosity to essentially a fully porous material.

## Claims

### Claim 1

A surface configured to at least partially surround an implant and to deliver a therapeutic agent, the surface having a finite thickness and comprising:
a controlled-permeability layer;
at least one therapeutic agent holding area positioned between said controlled-permeability layer and said implant; and
an in-growth scaffolding at least partially surrounding said controlled permeability layer configured for at least one of bone and tissue in-growth,
wherein said controlled-permeability layer and said at least one therapeutic agent holding area cooperate to control when said therapeutic agent is delivered.

### Claim 2 (depends on 1)

The surface of claim 1, wherein said at least one therapeutic agent holding area comprises a resorbable polymer containing a therapeutic agent.

### Claim 3 (depends on 1)

The surface of claim 1, wherein said at least one therapeutic agent holding area comprises a reservoir.

### Claim 4 (depends on 1)

The surface of claim 1, wherein said at least one therapeutic agent holding area comprises a plurality of reservoirs.

### Claim 5 (depends on 4)

The surface of claim 4, wherein each of said plurality of reservoirs comprises a first opening and a second opening, wherein said first opening opens into said controlled-permeability layer and said second opening connects to the distal end of at least one runner, and wherein each of said at least one runner has a proximal accessible end.

### Claim 6 (depends on 5)

The surface of claim 5, wherein said proximal accessible end has a marker.

### Claim 7 (depends on 5)

The surface of claim 5, wherein said at least one runner comprises a plurality of runners, and wherein said plurality of runners are connected via an interconnected runner network, and wherein said interconnected runner network has an accessible end.

### Claim 8 (depends on 7)

The surface of claim 7, wherein said accessible end has a marker.

### Claim 9 (depends on 1)

The surface of claim 1, wherein said at least one therapeutic agent holding area has a marker.

### Claim 10 (depends on 1)

The surface of claim 1, wherein said at least one therapeutic agent holding area is refillable with a therapeutic agent in vivo or ex vivo.

### Claim 11 (depends on 1)

The surface of claim 1, further comprising a first transitional layer interposed between said scaffolding and said controlled-permeability layer.

### Claim 12 (depends on 1)

The surface of claim 1, further comprising a second transitional layer interposed between said controlled-permeability and said implant.

### Claim 13 (depends on 1)

The surface of claim 1, wherein said scaffolding has openings which are substantially aligned with openings in said controlled-permeability layer.

### Claim 14 (depends on 1)

The surface of claim 1, wherein said therapeutic agent comprises at least one of a group consisting of a drug, a medicine, a pharmaceutical, a hormone, an antibiotic, a protein, a gene, a growth factor, and a bioactive material.

### Claim 15 (depends on 1)

The surface of claim 1, wherein said controlled-permeability layer has a diffusion rate that is uniform throughout the layer.

### Claim 16 (depends on 1)

The surface of claim 1, wherein said controlled-permeability layer has a first diffusion rate at a first region of layer and a second diffusion rate at a second region of the layer.

### Claim 17 (depends on 1)

The surface of claim 1, wherein said at least one therapeutic holding area has predetermined release rate of the said therapeutic agent.

### Claim 18 (depends on 1)

The surface of claim 1, wherein said ingrowth scaffolding comprises a plurality of bonded layers of porous material, each layer having a porosity between approximately 5% and approximately 95%, mean spacing of cells between approximately 0.05 mm and approximately 5 mm, and strut thickness between approximately 0.05 mm and approximately 2 mm, and wherein said porosity of said material is non-uniform across said plurality of layers.

### Claim 19 (depends on 18)

The surface of claim 18, wherein each of said layers have a different porosity.

### Claim 20 (depends on 18)

The surface of claim 18, wherein at least a region of the scaffolding has a stiffness that closely matches trabecular bone.

### Claim 21

A medical device comprising:
an implant having a surface configured to at least partially surround said implant and to deliver a therapeutic agent the surface having a finite thickness and: comprising
a controlled-permeability layer;
at least one therapeutic agent holding area positioned between said controlled-permeability layer and said implant; and
an in-growth scaffolding at least partially surrounding said controlled permeability layer configured for at least one of bone and tissue in-growth,
wherein said controlled-permeability layer and said at least one therapeutic agent holding area cooperate to control when said therapeutic agent is delivered.

### Claim 22 (depends on 21)

The medical device of claim 21, wherein said at least one therapeutic agent holding area comprises a resorbable polymer bead containing a therapeutic agent.

### Claim 23 (depends on 21)

The medical device of claim 21, wherein said at least one therapeutic agent holding area comprises a reservoir.

### Claim 24 (depends on 21)

The medical device of claim 21, wherein said at least one therapeutic agent holding area comprises a plurality of reservoirs.

### Claim 25 (depends on 24)

The medical device of claim 24, wherein each of said plurality of reservoirs comprises a first opening and a second opening, wherein said first opening opens into said controlled-permeability layer and said second opening connects to the distal end of at least one runner, and wherein each of said at least one runner has a proximal accessible end.

### Claim 26 (depends on 25)

The medical device of claim 25, wherein said accessible end has a marker.

### Claim 27 (depends on 25)

The medical device of claim 25, wherein said at least one runner extends out of said controlled-permeability layer.

### Claim 28 (depends on 25)

The medical device of claim 25, wherein a plurality of said at least one runners are connected via an interconnected runner network, and wherein said interconnected runner network has an accessible end.

### Claim 29 (depends on 28)

The medical device of claim 28, wherein said accessible end has a marker.

### Claim 30 (depends on 28)

The medical device of claim 28, wherein a portion of said interconnected runner network extends out of said controlled-permeability layer.

### Claim 31 (depends on 21)

The medical device of claim 21, wherein said at least one therapeutic agent holding area has a marker.

### Claim 32 (depends on 21)

The medical device of claim 21, wherein said at least one therapeutic agent holding is refillable with a therapeutic agent in vivo or ex vivo.

### Claim 33 (depends on 21)

The medical device of claim 21, wherein said implant is an orthopedic implant.

### Claim 34 (depends on 21)

The medical device of claim 21, wherein said implant contacts soft tissue.

### Claim 35 (depends on 21)

The medical device of claim 21, wherein said therapeutic agent comprises at least one of a group consisting of a drug, a medicine, a pharmaceutical, a hormone, an antibiotic, a protein, a gene, a growth factor, and a bioactive material.

### Claim 36

A method of delivering a therapeutic agent from an implant which has a surface configured to at least partially surround said implant and to deliver a therapeutic agent the surface having a finite thickness and comprising:
a controlled-permeability layer;
at least one therapeutic agent holding area positioned between said controlled-permeability layer and said implant; and
an in-growth scaffolding at least partially surrounding said controlled permeability layer configured for at least one of bone and tissue in-growth, and
wherein said controlled-permeability layer and said at least one therapeutic agent holding area cooperate to control when said therapeutic agent is delivered;
the method comprising:
releasing from said at least one therapeutic agent holding area a first therapeutic agent; and
diffusing said first therapeutic agent through said controlled-permeability layer and into said scaffolding to provide a therapeutic effect.

### Claim 37 (depends on 36)

The method of claim 36, further comprising refilling said at least one therapeutic agent holding area with a second therapeutic agent.

### Claim 38 (depends on 37)

The method of claim 37, further comprising locating said at least one therapeutic agent holding area.

### Claim 39 (depends on 37)

The method of claim 37, wherein said first and second therapeutic agents are the same.

### Claim 40 (depends on 37)

The method of claim 37, wherein said therapeutic agent comprises at least one of a group consisting of a drug, a medicine, a pharmaceutical, a hormone, an antibiotic, a protein, a gene, a growth factor, and a bioactive material.