Placental tissue grafts

• US 8,709,494 B2
• Filed: 07/30/2013
• Issued: 04/29/2014
• 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): Ford, Allison
• Application Number:
  US13/954,974
• Publication Number:
  US 20130337035A1
• Time in Patent Office: 273 Days
• Field of Search: None
• US Class Current: 424/583
• 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 tissue graft consisting essentially of one or more washed and/or substantially cleaned amnion layers and one or more washed and/or substantially cleaned chorion layers, wherein at least one of the amnion layers contains its fibroblast cell layer, and further wherein the amnion layer and the chorion layer are directly laminated to each other.

2. The dehydrated, laminated tissue graft of claim 1, wherein said assembled and laminated layers are dehydrated together in a drying fixture.

3. The dehydrated, laminated tissue graft of claim 1, wherein one or both of the one or more amnion layers and the one or more chorion layers 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. The dehydrated, laminated tissue graft of claim 1, consisting essentially of one amnion layer and one chorion layer.

6. A dehydrated, laminated tissue graft, wherein the tissue graft consists essentially of one or more amnion layers and one or more chorion layers wherein each of the amnion and chorion layers:

are separated from a placenta to provide separate layers of amnion and chorion,

washed and substantially cleaned without removal of the fibroblast cell layer from the amnion layer, and

are layered directly over each other and are laminated and heat dehydrated together to provide the dehydrated, laminated tissue graft.

7. The tissue graft of claim 6, consisting essentially of one amnion layer and one chorion layer.

8. The tissue graft of claim 6, wherein at least one of the amnion or chorion layers has been chemically decontaminated.

9. A dehydrated, laminated, placental tissue graft which is a laminate comprising two or more separated and washed layers which layers are selected from amnion and/or chorion wherein the layers are directly laminated to each other and at least one of said layers is an amnion layer which retains an epithelial cellular layer.

10. A dehydrated, laminated, placental tissue graft which is a laminate comprising two or more separated and washed layers which layers are selected from amnion and/or chorion wherein the layers are directly laminated to each other and at least one of said layers is an amnion layer which retains a fibroblast cellular layer.