Placental tissue grafts

• US 9,956,253 B2
• Filed: 10/13/2015
• Issued: 05/01/2018
• Est. Priority Date: 08/17/2006
• Status: Active Grant

• Current Assignee: Mimedx Group Incorporated
• Original Assignee: Mimedx Group Incorporated
• Inventors: Daniel, John
• Primary Examiner(s): FOX, ALLISON M
• Application Number:
  US14/881,536
• Publication Number:
  US 20160030634A1
• Time in Patent Office: 931 Days
• Field of Search: None
• CPC Class Codes: A61K 35/50 Placenta; Placental stem cells; Amniotic fluid; Amnion; Amniotic stem cells
• CPC Class Codes: A61L 2300/412 Tissue-regenerating or healing or proliferative agents
• CPC Class Codes: A61L 2300/60 characterised by a special physical form
• CPC Class Codes: A61L 2430/40 Preparation and treatment of biological tissue for implantation, e.g. decellularisation, cross-linking
• CPC Class Codes: A61L 27/3604 characterised by the human or animal origin of the biological material, e.g. hair, fascia, fish scales, silk, shellac, pericardium, pleura, renal tissue, amniotic membrane, parenchymal tissue, fetal tissue, muscle tissue, fat tissue, enamel
• CPC Class Codes: A61L 27/3683 subjected to a specific treatment prior to implantation, e.g. decellularising, demineralising, grinding, cellular disruption/non-collagenous protein removal, anti-calcification, crosslinking, supercritical fluid extraction, enzyme treatment
• CPC Class Codes: A61L 27/3691 characterised by physical conditions of the treatment, e.g. applying a compressive force to the composition, pressure cycles, ultrasonic/sonication or microwave treatment, lyophilisation
• CPC Class Codes: A61L 27/50 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body

Abstract

A method for preparing placenta membrane tissue grafts for medical use, includes obtaining a placenta from a subject, cleaning the placenta, separating the chorion tissue from the amniotic membrane, mounting a selected layer of either the chorion tissue or the amniotic membrane onto a drying fixture, dehydrating the selected layer on the drying fixture, and cutting the selected layer into a plurality of tissue grafts. Preferably, the drying fixture includes grooves or raised edges that define the outer contours of each desired tissue graft, after they are cut, and further includes raised or indented logos that emboss the middle area of the tissue grafts during dehydration and that enables an end user to distinguish the top from the bottom side of the graft. The grafts are comprised of single layers of amnion or chorion, multiple layers of amnion or chorion, or multiple layers of a combination of amnion and chorion.

Claims

1. A dehydrated, laminated bilayer tissue graft consisting of

a) a washed, cleaned and dehydrated amnion layer isolated from a placenta;

b) a washed, cleaned and dehydrated chorion layer isolated from a placenta;

wherein the amnion layer consists of an epithelial cellular layer, a basement membrane, a compact layer, and a fibroblast cellular layer, and further wherein the chorion is in direct contact with the amnion and the two layers are laminated together.

2. The dehydrated, laminated tissue graft of claim 1, wherein the amnion layer and the chorion layer are isolated from the same placenta.

3. The dehydrated, laminated tissue graft of claim 1, wherein one or both of the amnion layer and the chorion layer are treated with an antibiotic prior to lamination.

4. The dehydrated, laminated tissue graft of claim 1, wherein the tissue graft has been exposed to sterilizing conditions.

5. A dehydrated, laminated bilayer tissue graft, wherein the tissue graft consists of an amnion layer and a chorion layer, wherein the amnion layer consists of an epithelial cellular layer, a basement membrane, a compact layer, and a fibroblast cellular layer, and wherein each of the amnion and chorion layers:

a) is separated from a placenta to provide separated layers of amnion and chorion;

b) is washed and substantially cleaned while retaining the fibroblast cellular layer on the amnion layer; and

c) is layered directly over the other and heat dehydrated and laminated to provide the dehydrated, laminated bilayer tissue graft.

6. The dehydrated, laminated tissue graft of claim 5, wherein at least one of the amnion layer or chorion layer has been chemically decontaminated.

7. A dehydrated, laminated placental tissue graft which is a laminate consisting of two washed layers,

wherein a first of said layers is an amnion layer which consists of an epithelial cellular layer, a basement membrane, a compact layer, and a fibroblast cellular layer, and a second of said layers is (i) amnion that consists of an epithelial cellular layer, a basement membrane, and a compact layer;

(ii) amnion that consists of an epithelial cellular layer, a basement membrane, a compact layer, and a fibroblast cellular layer;

or (iii) chorion,

wherein the first and second layers are dehydrated and laminated to each other;

and wherein the layers were separated prior to being laminated to each other.