Placental tissue grafts

• US 9,433,647 B2
• Filed: 03/21/2014
• Issued: 09/06/2016
• 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:
  US14/222,510
• Publication Number:
  US 20140283990A1
• Time in Patent Office: 900 Days
• Field of Search: None
• US Class Current: 1/1
• 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 method for forming a dehydrated, laminated tissue graft, comprising the steps of:

a) placing a first wet placental tissue onto a receiving surface of a drying fixture, wherein the receiving surface includes a slightly raised or indented texture or design adapted to provide a label into the placental tissue

b) placing at least one additional wet placental tissue adjacent to the first wet placental tissue;

c) drying the placental tissues under conditions using heat, such that a dehydrated, laminated tissue graft having a label is formed; and

d) removing the tissue graft from the drying fixture, wherein the receiving surface allows the tissue graft to be removed while maintaining the label;

wherein when at least one placental tissue is an amnion, said method does not substantially remove all of the epithelial cells on at least one amnion.

2. The method of claim 1, wherein the receiving surface comprises polytetrafluoroethylene.

3. The method of claim 1, wherein the receiving surface comprises polyoxymethylene.

4. The method of claim 1, wherein the first wet placental tissue and/or at least one additional wet placental tissue is amnion.

5. The method of claim 1, wherein the first wet placental tissue and/or at least one additional wet placental tissue is chorion.

6. The method of claim 1 wherein the first wet placental tissue and/or at least one additional wet placental tissue comprises at least one cellular layer.

7. The method of claim 6, wherein the at least one cellular layer is a fibroblast cellular layer.

8. The method of claim 7, wherein the fibroblast cellular layer is adjacent to the next placental tissue.

9. The method of claim 1 wherein the slightly indented texture or design comprises a plurality of grooves.

10. The method of claim 1 wherein the slightly raised texture or design comprises a plurality of raised edges or blades.

11. The method of claim 9, wherein the plurality of grooves defines a product space, wherein the texture or design is an indented asymmetric texture within the product space which has an otherwise smooth surface, such that a portion of the placental tissue placed within the product space molds around the texture thereby creating an asymmetric label on the placental tissue grafts.

12. The method of claim 10, wherein the plurality of raised edges or blades defines a product space, wherein the texture or design is a raised asymmetric texture within the product space which has an otherwise smooth surface, such that a portion of the placental tissue placed within the product space molds around the texture thereby creating an asymmetric label on the placental tissue grafts.