Amnion tissue grafts and methods of preparing and using same

Abstract

The invention provides method for preparing amnion tissue grafts, as well as the grafts themselves. In specific embodiments, the tissue graft comprises a single layer of dried amnion from an umbilical cord.

Description

(19) *EP004663211A2* (11) EP 4 663 211 A2 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: 17.12.2025 Bulletin 2025 / 51 (21) Application number: 25211664.5 (22) Date of filing: 02.11.2017 (51) International Patent Classification (IPC): A61L 27 / 36 (2006.01) (52) Cooperative Patent Classification (CPC): A61L 27 / 3604; A61L 27 / 3683; A61L 27 / 3687 (84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (30) Priority: 02.11.2016 US 201662416528 P (62) Document number(s) of the earlier application(s) in accordance with Art. 76 EPC: 17866477.7 / 3 534 981 (71) Applicant: AxoGen Corporation Alachua, Florida 32615 (US) (72) Inventor: DEISTER, Curt Alachua, 32615 (US) (74) Representative: Mathys & Squire The Shard 32 London Bridge Street London SE1 9SG (GB) Remarks: This application was filed on 28‑10‑2025 as a divisional application to the application mentioned under INID code 62. (54) AMNION TISSUE GRAFTS AND METHODS OF PREPARING AND USING SAME (57) The invention provides method for preparing amnion tissue grafts, as well as the grafts themselves. In specific embodiments, the tissue graft comprises a single layer of dried amnion from an umbilical cord. EP 4 66 3 21 1 A 2 Processed by Luminess, 75001 PARIS (FR) Description CROSS-REFERENCE TO A RELATED APPLICATION

[0001] This application claims the benefit of U.S. provisional applicationSerial No. 62 / 416,528, filedNovember 2, 2016, which is incorporated herein by reference in its entirety. BACKGROUND

[0002] Tissue grafts are useful for various types of surgical procedures and wound treatments. The tissue used in graft procedures can be collected from humans or from animal specimens. Alternatively, graft tissue can be manufactured artificially. One source of human tissue, which has been utilized for decades in surgical procedures, is the placental membrane.

[0003] The placenta is an organ that develops during pregnancy to surround the fetus and connect it to the uterine wall. This temporary organ allows for transport of gases and nutrients to the fetus, while also providing other metabolic and endocrine functions. The placental membrane consists of two layers of tissue: amnion, the innermost layer surrounding the developing fetus, and chorion, an outer layer surrounding the amnion and fetus. The amniotic membrane forms an avascular, fluid-filled sac around the fetus, which holds and protects the fetus during development.

[0004] In addition to the amniotic sac, anothermajor placental component is the umbilical cord. This cord-like structure, which attaches a fetus to the placenta, provides nutrition and support to the developing embryo. A human umbilical cord is typically about 50‑60 cm long and 2 cm in diameter. It consists of blood vessels surrounded by a smooth, protective mesenchymal material known as Wharton’s jelly, all of which is contained in a tube formed of amnion.

[0005] Amnion tissue grafts are generally used to assist in tissue regeneration and aid in wound healing. Known clinical procedures or applications for amnion grafts include, but are not limited to, ocular reconstruction, burn treatment, gum tissue replacement, and general wound care.

[0006] Amnion tissue provides unique grafting characteristics when used for surgical procedures. Some amnion tissue grafts have the ability to self-adhere or to be fixed in place by, for example, fibrin glue or suturing.

[0007] While using fresh membrane is typically ideal, the limited timeframe available for storage of fresh tissue makes such use difficult. Thus, processing methods are needed to facilitate preserving and storing tissue until it is needed for surgical applications. The main goal of tissue processing and preservation is to retain the beneficial components of fresh tissue while achieving a shelf life long enough to last until surgery. When prepared properly, amnion tissue grafts can be stored for extended periods of time. BRIEF SUMMARY OF THE INVENTION

[0008] The subject invention provides methods for preparing amnion tissue grafts, as well as the grafts themselves. In specific embodiments, the tissue graft comprises a single membrane of dried amnion from an umbilical cord.

[0009] In one embodiment, the method comprises the steps of: a)makinga longitudinal cut in theamnionof anumbilical cord toexpose the contentsof the lumenof theumbilical cord; b) removing blood vessels and Wharton’s jelly from the lumen of the umbilical cord to produce a debrided amnion; c) optionally, incubating the debrided amnion in a holding solution; d) washing the debrided and, if performed, incubated, amnion in the holding solution; e) rinsing the washed amnion one or more times in a rinsing solution; and f) drying the rinsed amnion.

[0010] In another embodiment, a partially debrided amnion is obtained and further processed by washing, rinsing, and drying and optionally, holding before the washing step. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 shows Pressure and Temperature charts from drying runs. DETAILED DISCLOSURE OF THE INVENTION

[0012] Amniotic membrane forms the inner lining of the placenta and umbilical cord during fetal development. The amniotic membrane has three distinct layers; a single layer of epithelial cells, a thick basement membrane and a non- vascular stromal layer. It contains no HLA antigens or MHC molecules and is therefore an immunologically privileged 2 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 material. The primary structural component of amniotic membrane is extracellular matrix consisting of collagens and proteins such as fibronectin, proteoglycans, laminin and glycosaminoglycans. Other molecules found in amniotic membrane include growth factors, metalloproteinases and tissue inhibitors of metalloproteinases, which together with the extracellular matrix components may play a role in wound healing and cellular ingrowth.

[0013] The subject invention provides methods for preparing amnion tissue grafts, as well as the grafts themselves. In specific embodiments, the tissue graft comprises a dried single layer amnion from an umbilical cord.

[0014] In one embodiment, the method comprises the steps of: a)makinga longitudinal cut in theamnionof anumbilical cord toexpose the contentsof the lumenof theumbilical cord; b) removing blood vessels and Wharton’s jelly from the lumen of the umbilical cord to produce a debrided amnion; c) optionally, incubating the debrided amnion in a holding solution; d) washing the debrided and, if performed, incubated, amnion in the holding solution; e) rinsing the washed amnion one or more times in a rinsing solution; and f) drying the rinsed amnion.

[0015] In another embodiment, a partially debrided amnion is obtained and further processed by washing, rinsing, and drying and optionally, holding before the washing step. Selected Definitions

[0016] "Subject" refers to an animal, such as a mammal, for example a human. The methods described herein can be useful for isolating amnion from both humans and non-human animals. In some embodiments, the subject is a mammal. The invention can be used in a subject selected from non-limiting examples of a human, non-human primate, rat, mouse, pig, horse, cattle, dog or cat.

[0017] "Amnion" as used herein refers to amniotic membrane of an umbilical cord.

[0018] "Umbilical cord" refers to a cordlike structure containing blood vessels that attachesa fetus to theplacenta during gestation. An umbilical cord comprises a wall of amnion enclosing a lumen comprising, among other substances, Wharton’s jelly and blood vessels. Producing the Amnion Tissue Graft

[0019] In one embodiment, a longitudinal cut in the amnion is made along the full length of an umbilical cord. The umbilical cordcan thenbe laidout flat inapproximately rectangular shapewithamnionat thebottomand thecontentsof the lumenover theamnion.The luminal contentsof theumbilical cord canbe removed from theamnion in aprocess referred to as "debriding" the amnion. The process of debriding comprises separating the contents of the umbilical cord from the amnion using appropriate tools, for example, surgical tools such as forceps, scissors, and the like.

[0020] The purpose of the debriding step is to remove all or substantially all of the luminal contents.Wharton’s jelly is an amorphous gel-like mass; it may not be possible, or desirable, to remove 100% of theWharton’s jelly. Accordingly, for the purposes of the invention, "removingWharton’s jelly from the luminal contents of the umbilical cord"means thatmore than about 50%, 70%, 80%, 90%, 95%, and even more than 99%, of theWharton’s jelly from the lumen of an umbilical cord is separated from the amnion. Therefore, some Wharton’s jelly may be left in the debrided amnion.

[0021] In one embodiment, an amount of Wharton’s jelly remains that substantially or completely fills valleys between ridges that would otherwise exist in the amnion tissue.

[0022] In one embodiment, the debridement step is performed in a rinsing solution. In one embodiment, the rinsing solution is phosphate buffered saline comprising: 1) NaCl: 7 to 11 g / L; preferably, 8‑10 g / L; more preferably, about 9 g / L; 2) Anhydrous Na2HPO4: 0.2 to 1.5 g / L; preferably, about 0.5 to 1 g / L; more preferably, about 0.8 g / L; and 3) KH2PO4: 0.1 to 0.2 g / L; preferably, about 0.15 g / L.

[0023] At pH: 7 to 8.8; preferably about 7.4.

[0024] In a particular embodiment, the rinsing solution comprises about 9 g / LNaCl, about 0.8 g / L anhydrousNa2HPO4, about 0.14 g / L KH2PO4, at a pH of about 7.4.

[0025] In certain embodiments, the rinsing solution does not contain calcium or magnesium.

[0026] In one embodiment, the debrided amnion is stored in a holding solution for a holding period. The holding period can be about two to five hours, particularly, about two, three, four or five hours. The holding step can be performed at a temperature of between 20°C to 30°C, preferably, at about 25°C.

[0027] In one embodiment, the holding solution comprises: 3 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 1) Tween‑20: 0.4% to 0.6% (v / v); preferably about 0.5% (v / v); 2) An antimicrobial compound: For example, polyaminopropyl biguanide (also called, polyhexamethylene biguanide hydrochloride or PHMB) at 0.04% to 0.06% (w / v), preferably about 0.05% (w / v). In another embodiment, the antimicrobial compound is chlorhexidine gluconate at a concentration of, for example 0.01% to 1.5% and, more preferably, from 0.03% to 0.08%. Additional antimicrobial compounds, for example, antibiotics or antifungal agents and their appropriate concentrationsareknown toapersonof ordinary skill in theart andsuchembodimentsarewithin the purview of the invention; 3) NaCl: 7 to 10 g / L; preferably, 8‑9 g / L; more preferably, about 9 g / L; and 4) An appropriate buffer, at pH6.0 to 8.0, preferably, 6.5 to 7.0; preferably, about 6.6 to 6.8; andmore preferably, 6.7± 0.1. Anexample of a buffer that can be used in the holding solution is Bis-Tris Propanebuffer, 8 to 12mM; preferably, 9 to 11mM; more preferably, about 10 mM. Additional examples of buffers includeMES, Bis-Tris, ADA, ACES, PIPES, MOPSO, BES,MOPS, TES, HEPES, DIPSO,MOBS, TAPSO, HEPPSO, POPSO, EPPS (HEPPS), Tricine, Gly-Gly, Bicine, HEPBS, TAPS, AMPD, TABS, AMPSO, CHES, CAPSO, AMP, CAPS, and CAPS.

[0028] In a particular embodiment, the holding solution comprises about 0.5% (v / v) Tween‑20; about 9 g / L NaCl; about 0.05% (w / v) PHMB; and about 10 mM Bis-Tris Propane buffer at pH of 6.7 ± 0.1.

[0029] Inoneembodiment, thedebridedamnion,withorwithout theholdingstep, is storedatabout4°C forabout10 to15 hours before a washing step. The step of storing debrided amnion at 4°C can be performed in the holding solution.

[0030] In another embodiment, thedebridedamnion, eitherwithorwithout theholdingstep, iswashed inawashingstep. Preferably, the washing step comprises agitating the debrided amnion in the holding solution.

[0031] Agitation during the washing step can be performed, for example, on a shaker for about two to five hours, particularly, for about two, three, four, or five hours. Agitation can be performed at about 50 to 300 rotations per minute (RPM), preferably at about 100 to 200RPM,more preferably at about 125 to 175RPM, evenmore preferably, at about 150 RPM.

[0032] In one embodiment, a debrided amnion is stored in a holding solution in the holding step and the washing step is performed in the same holding solution by transferring the amnion to a shaker.

[0033] After the washing step, the washed amnion is rinsed in a rinsing step. The rinsing step is performed in the rinsing solution, described above. In a particular embodiment, the rinsing solution used in the rinsing step comprises about 9 g / L NaCl, about 0.8 g / L anhydrous Na2HPO4, and about 0.14 g / L KH2PO4, at a pH of about 7.4.

[0034] In one embodiment, the step of rinsing is performed three to five times in a rinsing solution. Each rinsing step can be performed for about 5 to 30 minutes; preferably, for about 10 to 25 minutes; and even more preferably, for about 15 minutes.

[0035] The rinsingstepcanbeperformedonashaker at about 50 to300RPM,preferably at about 100 to200RPM,more preferably at about 125 to 175 RPM, even more preferably, at about 150 RPM.

[0036] The step of rinsing is designed to remove components of thewashing solution from the graft aswell as remaining blood or debris from the debriding step.

[0037] In one embodiment, the rinsed amnion is dried. The step of drying can be performed for about 5 to 25 hours, preferably, for about 10 to 20hours, and evenmorepreferably, for about 15hours. In one embodiment, drying is performed at a pressure lower than the atmospheric pressure, for example, at a pressure of between about 15mBar to 60mBar. In a typical drying process under reduced pressure, a pressure of about 40 to 60 mBar, preferably, between 45 to 55 mBar, more preferably, about 50mBar is used at the beginning of the drying step. The pressure can change over time during the step of drying as shown in Figure 1. The pressure at the end of the drying process of about 12 to 16 hours can be, for example, about 10 to 15 mBar.

[0038] In a specific embodiment, the step of drying is performed for about 15 hours at a temperature of between 30°C and 40°C and under initial pressure of between about 50mBar, which reduces to a pressure of about 15mBar towards the end of the drying step.

[0039] A further embodiment of the invention provides amethod for preparing a dried amnionmembrane from umbilical cord, the method comprising the steps of: a) obtaining a partially-debrided amnion; b) removing, blood vessels and Wharton’s jelly to produce a debrided amnion; c) optionally, incubating the debrided amnion in a holding solution; d) washing the debrided and, if performed, incubated, amnion in the holding solution; e) rinsing the washed amnion one or more times in a rinsing solution; and f) drying the washed amnion.

[0040] The partially-debrided amnion can be obtained in a frozen state, in which case, the frozen partially-debrided amnion is thawedbefore furtherprocessing.Thawingcanbeperformedoverabout6 to20hours, preferablyoverabout8 to 4 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 15 hours, andmore preferably, over about 10 to 12 hours. Thawing can be performed at a temperature of between 20°C to 30°C, preferably, between 22°C to 28°C, even more preferably, at about 24°C to 25°C.

[0041] The steps of removing the blood vessels and the Wharton’s jelly to produce a debrided amnion, incubating the debrided amnion in a holding solution, washing the debrided and if performed, incubated, amnion in the holding solution, rinsing thewashedamniononeormore times in the rinsingsolution, anddrying the rinsedamnionaredescribedaboveand such description is applicable to the embodiment of the invention where a partially debrided amnion is the starting materials. Amnion Tissue Grafts

[0042] The umbilical cord / amnion tissue grafts produced according to the subject invention may be, for example,½ cm to 4 cm wide and, for example, 2 to 6 cm long.

[0043] In oneembodiment thegraft is providedwithan indiciumofwhich side is from theoutsideof theumbilical cordand which side is from the inside of the umbilical cord. In oneembodiment, the indicium is a tabprovidedat a specified corner of the graft. As used herein, reference to a "tab"means a protrusion out from the edge of the graft. The protrusionmay be, for example, in theshapeof a rectangle, squareor triangle. Inoneembodiment, to place thegraft endothelial sideup, the tab is in the upper left corner.When used in practice, the tab also helps a user to grasp the tissue graft with a tool, for example, a forceps. Tabs are also useful in repositioning the tissuegraft at a surgical site, for example, a user canmaneuver the tissue graft at the surgical site by grasping the tissue graft with a tool, for example, a forceps, and repositioning the tissue graft as desired.

[0044] The tissue grafts prepared according to the subject invention are processed such as they have less than 20% water content. Preferably, the water content is about 12% to about 18%. In preferred embodiments, the water content is 15% or less.

[0045] Thegraft preferablycontainsnobloodvessels,or chorion tissue.That is, thegraft consists,or consistsessentially of, amnion tissue, typically including some Wharton’s jelly.

[0046] Whendried (e.g., after processing), the tissue graft has a thickness of about 150µm to 250µm, preferably about 175µmto225µm.Asnotedabove, the tissuegrafts compriseanamountofWharton’sJelly thatmakes thesurfacesmooth (e.g., few, if any, ridges). Preferably, the graft hasuniform thickness, varying by less than20%, 15%, 10%, 5%, 2%, or even 1% across its surface.

[0047] The tissue graft can be sterilizedwith e-beam irradiation of about, for example, less than 25KGyand, preferably, about 15‑19 KGy.

[0048] The tissue grafts comprise no live cells, glycerol or ice crystals.

[0049] In one embodiment, the graft is treated with, for example, ascorbic acid to improve its whiteness.

[0050] In oneembodiment, thegraft is coated, or infused,with anantimicrobial composition that persistswith thegraft so as to reduce and / or prevent infections once the graft is implanted. The antimicrobial composition may be, for example, polyhexanide (polyhexamethylene biguanide, PHMB) or chlorhexidine gluconate (CHG) (or other salt thereof) in an amount such that microbes are exposed to about 0.01% to about 1.0%CHG and preferably about 0.02% to about 0.08%. Most preferably to concentration ofCHG is about 0.03% to0.05%.Thegraftmay comprise other substances including, but not limited to, growth factors,anti-inflammatoryagents, andstemcells.Theamnion tissuegraftsproducedaccording to the methodsdescribedherein showsimilar levels of bioactive compoundsaspresent in the amnionused toproduce the tissue graft. Such bioactive compounds include interleukins, tissue inhibitors of metalloproteinases, epidermal growth factor, fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and transforming growth factor present before and after processing. These bioactive compounds facilitate healing when the tissue grafts of the invention are placed are used in surgical procedures.

[0051] Advantageously, the amnion tissue grafts of the subject invention have sufficient strength to be sutured. The suture may be, for example, a size 7‑0, 8‑0, or even 9‑0 USP size or smaller suture, which advantageously does not tear through the graft.

[0052] The tissue graft may be packaged inside a first foil package that is sterile inside and out and placed within the sterile inside of a second package. Use of the Amnion Tissue Graft

[0053] The amnion tissue grafts can be used, for example, to assist in tissue regeneration and aid in wound healing. Exemplary clinical procedures or applications for the subject amnion grafts include, but are not limited to, tendon repair, dural defects, intra-abominable adhesions, peritoneal reconstructions, genital reconstruction, ocular reconstruction, burn treatment, gum tissue replacement, nerve repair, promote healing at surgical sites, and general acute and chronic wound care.

[0054] The tissue graft may be placed directly at the surgical site or rehydrated prior to placement. If rehydration is 5 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 desired, room temperature sterile saline or sterile Lactated Ringer’s solution (LRS) can be used for rehydration.

[0055] When placed at a surgical site, either as dry or after rehydration, the tissue grafts of the invention drape and conform to the tissue or organ on which they are placed. Thus, the tissue grafts can self-adhere to the tissue or organ on which theyare placed. Adherenceof the tissuegrafts to a tissueor anorgan canbe facilitated by suturing the tissuegraft to the site. The self-adherence property of the tissue grafts of the invention can be enhanced by designing the tissue grafts to have rounded corners. Rounding of the corners facilitate placement of the tissue grafts at a site in the body because the rounded corners conform to the target sitemore easily than sharp corners, for example, right angled corners. Although the tissue graft conforms and adheres to the tissue or organ, the tissue grafts have sufficient strength to be repositioned by a user, for example, a surgeon, without breaking or disintegrating.

[0056] When implanted the tissue graft remains in place for 8, 10, 12, 16 or more weeks. Advantageously, the tissue grafts of the subject invention can be used to help prevent or reduce scar tissue by favorably modifying the host immune response via, for example, a barrier function at the site of the injury.

[0057] As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicatesotherwise.Furthermore, to theextent that the terms "including," "includes," "having," "has," "with," or variants thereof are used in either the detailed description and / or the claims, such termsare intended to be inclusive in a manner similar to the term "comprising".

[0058] The term "about" or "approximately" means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitationsof themeasurement system.For example, "about" canmeanwithin 1ormore than1standarddeviation, per the practice in the art. Alternatively, "about" canmean a range of up to 0‑20%, 0 to 10%, 0 to 5%, or up to 1%of a given value. Alternatively, particularly with respect to biological systems or processes, the term can mean within an order of magnitude, preferablywithin 5-fold, andmore preferablywithin 2-fold, of a value.Where particular values are described in the application and claims, unless otherwise stated the term "about" meaning within an acceptable error range for the particular value should be assumed. In the context of compositions containing amounts of ingredients where the terms "about" or "approximately" are used, these compositions contain the stated amount of the ingredient with a variation (error range) of 0‑10% around the value (X ± 10%).

[0059] In the present disclosure, ranges are stated in shorthand to avoid having to set out at length and describe each and every valuewithin the range. Any appropriate valuewithin the range can be selected, where appropriate, as the upper value, lower value, or the terminus of the range. For example, a range of 0.1‑1.0 represents the terminal values of 0.1 and 1.0, as well as the intermediate values of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and all intermediate ranges encompassed within 0.1‑1.0, such as 0.2‑0.5, 0.2‑0.8, 0.7‑1.0, etc. Values having at least two significant digits within a range are envisioned, for example, a range of 5‑10 indicates all the values between 5.0 and 10.0 as well as between 5.00 and 10.00 including the terminal values.

[0060] All patents, patent applications, provisional applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.

[0061] Following are examples which illustrate procedures for practicing the invention. These examples should not be construed as limiting. All percentages are by weight and all solvent mixture proportions are by volume unless otherwise noted. EXAMPLE 1 - BENCH-TOP EXECUTION OF A HUMAN UMBILICAL CORD MEMBRANE PROCESSING

[0062] This Example provides a procedure for extraction of materials from the tissue and retention of process residuals in the tissue.

[0063] The aqueous processing time used in this Example was intended to maximize the potential for extracting materials, such as growth factors or components of the extracellular matrix, from the tissue before testing. Using milder processing conditions less extraction occurs.

[0064] Additionally, the use of tissue that was prepared after recovery and before freezing by having the cord cut open andbulk tissue removed from thestromal face,maximizes thesurfacearea for diffusionofmaterialsout of the tissueduring the recovery process and the thawing before debridement. Reducing times and volumes for the rinse series between the detergentwashand thedryingprocess increases thepotential for retentionofprocessingagentsandsomaximizes the risk of affecting biocompatibility.

[0065] Equipment: 1. Shaker incubator 2. Biosafety cabinets 3. Vacuum drying oven 4. Vacuum Sealer 6 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 5. Balance 6. Push gauge 7. Refrigerator Debridement

[0066] Tissuewas obtained in the frozen state with significant debridement already conducted. This "pre-debridement" removed bulk tissue and variable amounts of the blood vessels. Thawing the frozen tissue was conducted at ambient temperature (~24°C) overnight. Average thaw time was 15:21 hr with a range of 14:34 to 17:03 hrs.

[0067] Debridement involved cutting open and removing any remaining blood vessels with forceps. Bulk tissue (principally Wharton’s Jelly) was then removed with curved iris scissors until all tissue above the plane of the tissue that could be gripped firmly between Adson forceps (e.g., tissue "ridges" that can be gripped without also gripping the membrane itself) was removed.

[0068] The average cord length was 44.5 cm (32 to 68 cm range). Debridement produced a wet tissue membrane that was about 1300 ± 300 microns thick with a range of 510 to 1900 microns.

[0069] The unprocessed tissue membranes were collected immediately after debridement and after measurements were made, the membranes were stored in sterile conical tubes in a refrigerator until the drying step.

[0070] Processed samples were also collected immediately after debridement and then measured but were then processed with the remainder of the cord before drying. Processing

[0071] Table1belowshows thedurationsandset-pointsof theprocess run in thisExample. n=3 for the threeprocessing runs except where noted when the step references individual donors. Table 1. Processing parameters Avg. value Min Max Pre-rinse (Step 1b) Duration (n = 12) 1:47 1:01 2:48 Volume of Sol. F (L) 2 + / ‑ 0.05 NA NA Temperature (°C) (set-point) 28 NA NA RPM’s (set-point) 150 NA NA Prost-Debridement hold (Step 2) Duration (hr) 3:00 3:00 3:02 Volume of Sol. H (L) 2 + / ‑ 0.05 NA NA Room Temperature, No agitation Yes NA NA Wash (Step 3) Solution was not changed between the holding and the washing step, i.e., the solution used in the holding step is used while shaking in the washing step. Duration (hr) 3:33 3:30 3:38 Temperature (°C) (set-point) 30.0 NA NA RPM’s (set-point) 150 NA NA Rinse #1 (Step 4) Duration (min) 10 10 11 Volume of Sol F (L) 1.5 + / ‑ 0.05 NA NA Temperature (°C) (set-point) 22.0 NA NA RPM’s (set-point) 130 NA NA Rinse #2 (Step 5) 7 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 (continued) Table 1. Processing parameters Avg. value Min Max Duration (min) 10 10 10 Volume of Sol F (L) 1.5 + / ‑ 0.05 NA NA Temperature (°C) (set-point) 22.0 NA NA RPM’s (set-point) 130 NA NA Rinse #3 (Step 6) Duration (min) 10 10 10 Volume of Sol. F (L) 1.5 + / ‑ 0.05 NA NA Temperature (°C) (set-point) 22.0 NA NA RPM’s (set-point) 130 NA NA Rinse #4 (Step 7) Duration (min) 11 10 13 Volume of Sol. F (L) 1.5 + / ‑ 0.05 NA NA Temperature (°C) (set-point) 22.0 NA NA RPM’s (set-point) 130 NA NA Drying (Step 8) Duration, hr (start to door open) 15.4 15.4 15.5 Solution F is rinsing solution and Solution H is holding solution. Drying

[0072] Drying was performed as described below. Table 2. Drying program used (from Table 2 of protocol) Drying step Temperature (°C) Pressure (mBar) Time (hr) (Start) / (Finish) (Start) / (Finish) Step 1 (start step) Ambient / 35 Ambient / 35 NA. till conditions met Step 2 35 / 35 35 / 15 1 min (note pressure will not be reached) Step 3 35 / 35 15 / 15 15 Total time ~15 hrs Time weighted average tem- perature 35 °C (approximate, timed steps only) Time weighted average pressure 15 mBar (approximate, timed steps only)

[0073] The drying procedure dried the tissue at about 30°C to 40°C, preferably, about 33°C to 37°C, even more preferably about, 34°C to 36°C, and particularly, about 35°C. The drying step is performed in amedium vacuum. The final vacuumpressure (absolute) can be about 10 to 20mBar, preferably, about 12 to 18mBar, evenmore preferably, about 14 to16mBar, andparticularly, about 15mBar.However, thevacuumpressureat any timeduring thedryingprocess is related to the water content of the tissue.

[0074] The drying timewas 15‑16 hours (note that the actual timemay vary as the 1st step continues until pressure and temperature aremet andwill vary based on initial conditions). For example, in one embodiment, the required temperature and pressure are reached within about 1 to 10 minutes, in about 2 to 5 minutes, or in about 2 to 3 minutes. 8 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55

[0075] The pressure and temperature profiles of three development runs are shown in Figure 1.

[0076] In all three runs, the chamber was at approximately 15 mBar by 730 minutes after the start of the run. Condensation was observed on the inside of the front window of the chamber in approximately the same timeframe as the pressure increase observed at about 50minutes into the run. A "shoulder" is observed in the pressure plot between 30 and 25mBar whichmight represent the end of primary drying (i.e. removal of water not bound to othermolecules). The chamber temperature varied less than 0.5°C from the set-point through the run after the set-point was reached.

[0077] To reduce the possibility of absorbingmoisture from the atmosphere, the drying assemblies still in the drying bag were placed in poly bags and sealed with a zip tie until used (if sizing and packaging was not started immediately). The processed and unprocessed samples showed an average loss of mass on drying of 95% (Table 3). 9 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 Ta bl e 3. W et an d dr y w ei gh ts of tis su e sa m pl es R un #1 R un #2 R un #3 Lo t# 1 Lo t# 2 Lo t# 3 Lo t# 4 Lo t# 1 Lo t# 2 Lo t# 3 Lo t# 4 Lo t# 1 Lo t# 2 Lo t# 3 Lo t# 4 W et w ei gh t, g (u n- pr oc es se d sa m pl e) 1. 12 1 1. 81 1. 43 4 1. 52 2 1. 39 4 1. 47 9 1. 71 1. 67 3 1. 39 2 2. 39 9 1. 43 3 1. 66 2 D ry w ei gh t, g (u n- pr oc es se d sa m pl e) 0. 07 7 0. 09 0. 07 5 0. 07 8 0. 05 4 0. 07 7 0. 09 9 0. 09 1 0. 07 9 0. 11 2 0. 08 2 0. 08 1 W et w ei gh t, g (p ro - ce ss ed sa m pl e) 1. 04 7 1. 39 9 1. 54 7 1. 44 5 1. 28 5 1. 92 2. 28 8 1. 71 9 0. 85 1. 40 1 1. 57 4 1. 85 5 D ry w ei gh t, g (p ro - ce ss ed sa m pl e) 0. 05 3 0. 06 9 0. 05 8 0. 16 3 0. 05 8 0. 09 9 0. 08 9 0. 09 1 0. 04 5 0. 06 0. 08 4 0. 06 9 % de cr ea se in U n- pr oc es se d w ei gh t 93 .1 % 95 .0 % 94 .8 % 94 .9 % 96 .1 % 94 .8 % 94 .2 % 94 .6 % 94 .3 % 95 .3 % 94 .3 % 95 .1 % % de cr ea se in Pr o- ce ss ed w ei gh t 94 .9 % 95 .1 % 96 .3 % 88 .7 % 95 .5 % 94 .8 % 96 .1 % 94 .7 % 94 .7 % 95 .7 % 94 .7 % 96 .3 % Av g % de cr ea se in U np ro ce ss ed w ei gh t 94 .7 % SD 0. 7% Av g % de cr ea se in w ei gh t, al ls am pl es 94 .8 % SD 1. 5% Av g % de cr ea se in Pr oc es se d w ei gh t 94 .8 % SD 2. 0% W ei gh ts fro m sc al e re su lt in 2 si gn ifi ca nt fig ur es .P er ce nt ag es ar e sh ow n at 3 si gn ifi ca nt fig ur es . 10 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 Appearance and final sizing

[0078] Samples were manually sized using a scalpel and ruler. Lots with samples intended for bioburden testing were sized first using an autoclaved cutting board. Subsequent Lots within each Run were sized using a disposable cutting boardwith a pre-printed cmscale grid. This disposable cutting boardwasnot steamsterilizable, butwas cleanedwith 70% isopropyl alcohol and air-dried prior to use. Tissue Thicknesses

[0079] Accounting for the significant digits of themeasurement,wet tissueafter debridementwas1300±300microns in thickness and dry tissue was 200 ± 60 microns in thickness. The observed range for wet tissue (24 samples; 64 measurements) was 510 to 1900 microns. The observed range for dry tissue (24 samples; 72 measurements) was 50 to 300 microns. 11 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 Ta bl e 6. Aq ue ou s Pr oc es s C on di tio ns Te st ed (th is pr ot oc ol ) A lte rn at iv e Pr oc es s Pr oc es s St ep Ti m e Ag ita tio n se tp oi nt (rp m ) Te m pe ra tu re se tp oi nt (° C ) So lu tio n Vo lu m e (L ) Ti m e Ag ita tio n (rp m ) Te m pe ra tu re (° C ) So lu tio n Vo lu m e (L ) St ep 1, D eb rid em en t Pe rfo rm as ra pi dl y as po ss ib le in Bi os af et y C ab in et st or ag e so lu tio n (0 .9 % sa lin e) m in im al vo lu m e to ke ep tis su e w et Pe rfo rm as ra pi dl y as po ss ib le in Bi os af et y C ab in et st or ag e so lu tio n (0 .9 % sa lin e) N A, m in im al vo lu m e to ke ep tis su e w et St ep 1b ,P os t-d eb rid em en t in cu ba tio n (e ac h do no r en te rs at a di ffe re nt tim e) 1: 47 hr (1 :0 1‑ 2: 48 ) 15 0 28 F 2 ± 0. 05 St ep no ti n al te rn at iv e pr oc es s St ep 2, Po st -d eb rid em en t ho ld 3: 00 hr (3 :0 0‑ 3: 02 ) 0 am bi en t( he ld in ho od ) H 2 ± 0. 05 0‑ 2. 5 hr 0 am bi en t H 1. 95 ± 0. 05 St ep 3, Pr oc es s W as h 3: 33 hr (3 :3 0‑ 3: 38 ) 15 0 30 H N o so lu tio n ch an ge 1‑ 1. 5 hr 14 0± 5 26 ± 2 H N o so lu tio n ch an ge St ep 4, Pr oc es s R in se #1 10 m in (1 0‑ 11 ) 13 0 22 F 1. 5± 0. 05 15 ‑4 0 m in 14 0± 5 26 ± 2 F 1. 95 ± 0. 05 St ep 5, Pr oc es s R in se #2 10 m in (1 0‑ 10 ) 13 0 22 F 1. 5± 0. 05 15 ‑4 0 m in 14 0± 5 26 ± 2 F 1. 95 ± 0. 05 St ep 6, Pr oc es s R in se #3 10 m in (1 0‑ 10 ) 13 0 22 F 1. 5± 0. 05 15 ‑4 0 m in 14 0± 5 26 ± 2 F 1. 95 ± 0. 05 St ep 7, Pr oc es s R in se #4 11 m in (1 0‑ 13 ) 13 0 22 F 1. 5± 0. 05 15 ‑4 0 m in 14 0± 5 26 ± 2 F 1. 95 ± 0. 05 To ta la qu eo us pr oc es st im e 7: 15 hr (7 :1 2‑ 7: 21 )n ot in cl ud in g tim e of ch an ge s 2: 00 to 6: 40 no ti nc lu di ng tim e of ch an ge s 12 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 Table 7. Drying Process Conditions This Example Alternative Process Drying step Temperature (°C) Pressure (mBar) Time (hr) Temperature (°C) Pressure (mBar) Time (hr) (Start) / (Finish) (Start) / (Finish) (Start) / (Finish) (Start) / (Finish) Step 1 (start step) Ambient / 35 Ambient / 35 Till conditions met Ambient / 35 Ambient / 35 Till conditions met Step 2 35 / 35 35 / 15 1 min (note pressure will not be reached) 35 / 35 35 / 15 1 min (note pres- sure will not be reached) Step 3 35 / 35 15 / 15 15 35 / 35 15 / 15 16 Step 4 NA Shut off heating element (set to 20°C) and vent chamber with nitrogen then shut down system. This holds the tissue in an inert environment (~1 atm of nitrogen and approxi- mately ambient temperature) until the chamber is opened. Total time (start to door open or nitrogen purge) 15.4 hr (15.4‑15.5) ~16.5 hrs Conclusions

[0080] Tissue thawing was conducted at ambient temperature (~24°) overnight, 14‑18 hrs. Debridement resulted in a wet membrane of about 1.3 mm thickness, which was reduced after drying to about 0.2 mm. The weight loss on drying observed was about 95% for all samples.

[0081] Table 6 summarizes the aqueous processing conditions tested and potential conditions for an alternative process. The potential alternative process conditions are selected to be overall milder processing conditions for the tissue (principally less total contact time) while providing greater potential to remove residual processing agents (increased time, agitation, and temperature in Steps 3‑7).

[0082] Table 7 summarizes the drying processing conditions tested and potential conditions for an alternative process. The potential alternative process conditions are selected ensure that the drying observed is at least as robust as that observed in this protocol.

[0083] Alternative solutions to the nitrogen purge as a terminal hold step are possible, such as shutting the heating element off and maintaining vacuum. The samples made under this protocol are appropriate for characterization testing.

[0084] The disclosure of this application also includes the following numbered clauses: Clause 1. Amethod for preparing a dried amnion tissue graft from an umbilical cord, themethod comprising the steps of: a)makinga longitudinal cut inamnionofanumbilical cord that hasa lumen inorder toexposecontentsof the lumen; c) removing, from the contents of the lumen, blood vessels and Wharton’s jelly to produce a debrided amnion; d) optionally, incubating the debrided amnion in a holding solution; e) washing the debrided and if performed, incubated, amnion in the holding solution; f) rinsing the washed amnion one or more times in a rinsing solution; and g) drying the rinsed amnion. Clause 2. The method of clause 1, wherein the longitudinal cut is made along the full length of the cord. Clause 3. The method of clause 1 or 2, wherein the holding solution comprises: a) Tween‑20: 0.4% to 0.6% (v / v), preferably about 0.5% (v / v), b) an antimicrobial compound, c) NaCl: 7 to 10 g / L, d) a buffer at pH of 6.5 to 7.0. Clause 4. Themethodof any of clauses 1‑3,wherein theholding solution comprises: a) 0.5% (v / v) Tween‑20; b) about 0.05% (w / v) Polyhexamethylene biguanide hydrochloride; c) NaCl: 9 g / L; d) an appropriate buffer, pH 6.7 ± 0.1. Clause 5. Themethod of any of clauses 1‑4,wherein the step of washings comprises agitating the debrided amnion in the holding solution. 13 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 Clause 6. The method of any of clauses 1‑5, wherein the step of washing is conducted for about three hours and the agitation is performed at about 100 to 200 rotations per minute. Clause 7. Themethod of any of clauses 1‑6,wherein the rinsing solution comprises: a)NaCl: 7 to 10 g / L, b) anhydrous Na2HPO4: 0.5 to 1.5 g / L, c) KH2PO4: 0.1 to 0.2 g / L, at a pH of about 7.4. Clause 8. Themethod of any of clauses 1‑7, wherein the rinsing solution comprises about 9 g / LNaCl, about 0.795 g / L anhydrous Na2HPO4, about 0.144 g / L KH2PO4, at a pH of about 7.4. Clause9. Themethodof anyof clauses1‑8,wherein thestepof rinsing is performed for three to five times in the rinsing solution. Clause 10. The method of clause 9, wherein each rinsing step is performed for about 10 minutes at about 100 to 200 RPM. Clause11. Themethodof anyof clauses1‑10,wherein thedebridedamnion is storedat about 4°Cbefore thewashing step. Clause 12. The method of any of clauses 1‑10, wherein the step of drying is performed for about 15 hours at a temperature of between 30°C and 40°C and under a pressure of between 15 to 50 mBar. Clause 13. Amethod for obtaining adried amnionmembrane fromumbilical cord, themethod comprising the steps of: a) obtaining a partially debrided amnion; b) removing, the blood vessels and theWharton’s jelly to produce a debrided amnion; c) optionally, incubating the debrided amnion in a holding solution; d) washing the debrided and if performed, incubated, amnion in the holding solution; e) rinsing thewashed amnion one ormore times in a rinsing solution; and f) drying the rinsed amnion. Clause 14. The method of clause 13, wherein the partially debrided amnion is obtained in a frozen state and the method comprises thawing the frozen partially debrided amnion. Clause 15. The method of clause 14, wherein the thawing is performed at 24°C for about 10‑15 hours. Clause 16. Themethod of any of clauses 13‑15, wherein the holding solution comprises: a) Tween‑20: 0.4% to 0.6% (v / v), preferably about 0.5% (v / v), b) an antimicrobial compound, c) NaCl: 7 to 10 g / L, d) a buffer at pH of 6.5 to 7.0. Clause 17. The method of any of clauses 13‑16, wherein the holding solution comprises: a) 0.5% (v / v) Tween‑20; b) about 0.05% (w / v)Polyhexamethylenebiguanidehydrochloride; c)NaCl: 9 g / L; d) anappropriate buffer, pH6.7±0.1. Clause 18. The method of any of clauses 13‑17, wherein the step of washings comprises agitating the debrided amnion in the holding solution. Clause 19. Themethod of clause 18, wherein the step of washing is conducted for about three hours and the agitation is performed at about 100 to 200 rotations per minute. Clause 20. The method of any of clauses 13‑19, wherein the rinsing solution comprises: a) NaCl: 7 to 10 g / L, b) anhydrous Na2HPO4: 0.5 to 1.5 g / L, c) KH2PO4: 0.1 to 0.2 g / L, at a pH of about 7.4. Clause 21. Themethod of any of clauses 13‑20,wherein the rinsing solution comprises about 9 g / LNaCl, about 0.795 g / L anhydrous Na2HPO4, about 0.144 g / L KH2PO4, at a pH of about 7.4. Clause 22. The method of any of clauses 13‑21, wherein the step of rinsing is performed for three to five times in a rinsing solution. Clause 23. Themethod of clause 22, wherein each rinsing step is performed for about 10minutes at about 100 to 200 RPM. Clause 24. The method of any of clauses 13‑23, wherein the debrided amnion is stored at about 4°C before the washing step. Clause 25. The method of any of clauses 13‑24, wherein the step of drying is performed about 15 hours at a temperature of between 30°C and 40°C and under a pressure of between 15 to 50 mBar. Clause 26. An amnion tissue graft prepared by the method of any of the preceding clauses. Clause27.Anamnion tissuegraft comprisingasinglemembraneof umbilical cordamnion, sufficientWharton’s jelly to create a smooth service, less than 20% water and a thickness of 150 to 250 µm. Clause 28. The tissue graft, according to clause 27, that does not comprise glycerol. Clause 29. The tissue graft, according to any of clauses 27‑28, consisting essentially of a single layer of amnion, sufficient Wharton’s jelly to create a smooth service, less than 20% water and a thickness of 150 to 250 µm. Clause30.The tissuegraft, according toanyof clauses27‑29, havingsufficient strength tobesuturedwithan8‑0USP suture. Clause 31. The tissue graft, according to any of clauses 27‑30, whose thickness does not vary by more than 20%. Clause 32. The tissue graft, according to any of clauses 27‑31, comprising an indicium that distinguishes epithelial side of the tissue graft from the stromal side of the tissue graft. Clause33.The tissuegraft, according to clause32,wherein the indicium isaprotrusionout fromaspecifiedareaof the graft. Clause 34. The tissue graft, according to clause 33, wherein the protrusion is a rectangular, square, or triangular tab. Clause 35. The tissue graft, according to any of clauses 33‑34, wherein the protrusion is designed to be suitable for being grasped by a forceps. 14 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 Clauses 36. The tissue graft, according to any of clauses 27‑35, comprising similar levels of bioactive compounds as present in the amnion used to produce the tissue graft. Clause 37. The tissue graft, according to clause 36, wherein the bioactive compounds comprise interleukins, tissue inhibitors of metalloproteinases, epidermal growth factor, fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and transforming growth factor. Clause 38. The tissue graft, according to any of clauses 27‑37, wherein the tissue graft, when placed on a tissue or an organ, conforms and adheres to the tissue or organ. Clause 39. The tissue graft, according to clause 38, wherein the tissue graft, after conforming and adhering to the tissue or organ, repositions without disintegrating or breaking when repositioned by a user. Clause 40. The tissue graft, according to any of clauses 27‑39, wherein the tissue graft, when placed on the tissue or the organ, remains in place for at least 8 weeks, 10 weeks, 12 weeks, 16 weeks or longer. Clause 41. The tissue graft, according to clause 40, wherein the tissue graft, when placed on the tissue or the organ, remains in place for at least 16 weeks. Claims 1. A method for preparing a dried amnion tissue graft from an umbilical cord, the method comprising the steps of: making a longitudinal cut in an amnion of the umbilical cord that has a lumen in order to expose contents of the lumen; removing, from the contents of the lumen, blood vessels and more than 50% of Wharton’s jelly, but leaving some Wharton’s jelly, to produce a debrided amnion; washing the debrided amnion; rinsing the washed amnion one or more times; and drying the rinsed amnion. 2. The method of claim 1, further comprising: incubating the debrided amnion before washing the debrided amnion. 3. The method of claim 1 or 2, wherein washing the amnion includes washing the amnion in a holding solution that comprises a buffer at pH of 6.5 to 7.0, and wherein the holding solution comprises: Tween‑20: 0.5% (v / v); 0.05% (w / v) Polyhexamethylene biguanide hydrochloride; NaCl: 9 g / L; and a buffer at pH of 6.7 ± 0.1. 4. The method of any of claims 1 to 3, wherein the Wharton’s jelly present in the umbilical cord amnion substantially or completely fills valleys between ridges on a surface of the debrided amnion. 5. The method of any of claims 1 to 4, wherein the step of washing is conducted for two to five hours and comprises agitation performed at 50 rotations per minute to 300 rotations per minute. 6. Themethod of any of claims 1 to 5, wherein the step of washing is conducted for three hours and comprises agitation performed at 100 rotations per minute to 200 rotations per minute. 7. The method of any of claims 1 to 6, wherein the step of rinsing the washed amnion includes rinsing the amnion in a rinsing solution that has a pH of 7.4 and comprises: NaCl: 7 to 10 g / L, anhydrous Na2HPO4: 0.5 to 1.5 g / L, and KH2PO4: 0.1 to 0.2 g / L. 8. The method of claim 7, wherein the rinsing solution comprises: NaCl: 9 g / L; anhydrous Na2HPO4: 0.795 g / L; and 15 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 KH2PO4: 0.144 g / L. 9. Themethod of any of claims 1 to 8, wherein the step of rinsing is performed for three to five times in a rinsing solution, and wherein each rinsing step is performed for between 5 and 30 minutes at 50 rotations per minute to 300 rotations per minute. 10. Themethod of any of claims 1 to 9, wherein the debrided amnion is stored at 4°C before the washing step, or wherein the step of drying is performed for 15 hours under a pressure of between 15 and 50mBar at a temperature of between 30°C and 40°C. 11. An amnion tissue graft comprising: a single membrane of umbilical cord amnion, wherein a smooth surface is created by Wharton’s jelly, and wherein a thickness of the tissue graft does not vary by more than 20%. 12. The amnion tissue graft according to claim 11, wherein the amnion tissue graft is formed by removing, from the umbilical cord amnion, blood vessels and more than 50% of Wharton’s jelly, but leaving some Wharton’s jelly. 13. Theamnion tissuegraft according to claim12,whereinWharton’s jelly substantially or completely fills valleysbetween ridges on a surface of the amnion to form the smooth surface. 14. The amnion tissue graft according to any of claims 11 to 13, further comprising an indicium that distinguishes the epithelial side of the amnion tissue graft from the stromal side of the amnion tissue graft; optionally, wherein the indicium is a protrusion out from a specified area of the amnion tissue graft; optionally, wherein the protrusion is designed to be suitable for being grasped by a forceps, and wherein the amnion tissue graft comprises rounded corners such that, when the amnion tissue graft is placed on a tissue or an organ, the amnion tissue graft is configured to conform and adhere to the tissue or the organ. 15. The amnion tissue graft according to any of claims 11 to 14, further comprising one or more bioactive compounds at similar levels of bioactive compounds as present in the amnion used to produce the tissue graft, wherein the one or more bioactive compounds include one or more of: interleukins, tissue inhibitors of metalloproteinases, epidermal growth factor, fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and transforming growth factor. 16 EP 4 663 211 A2 5 10 15 20 25 30 35 40 45 50 55 17 EP 4 663 211 A2 18 EP 4 663 211 A2 REFERENCES CITED IN THE DESCRIPTION This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard. Patent documents cited in the description • US 62416528

[0001] (19) *EP004663211A3* (11) EP 4 663 211 A3 (12) EUROPEAN PATENT APPLICATION (88) Date of publication A3: 18.02.2026 Bulletin 2026 / 08 (43) Date of publication A2: 17.12.2025 Bulletin 2025 / 51 (21) Application number: 25211664.5 (22) Date of filing: 02.11.2017 (51) International Patent Classification (IPC): A61L 27 / 36 (2006.01) (52) Cooperative Patent Classification (CPC): A61L 27 / 3604; A61L 27 / 3683; A61L 27 / 3687 (84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (30) Priority: 02.11.2016 US 201662416528 P (62) Document number(s) of the earlier application(s) in accordance with Art. 76 EPC: 17866477.7 / 3 534 981 (71) Applicant: AxoGen Corporation Alachua, Florida 32615 (US) (72) Inventor: DEISTER, Curt Alachua, 32615 (US) (74) Representative: Mathys & Squire The Shard 32 London Bridge Street London SE1 9SG (GB) (54) AMNION TISSUE GRAFTS AND METHODS OF PREPARING AND USING SAME (57) The invention provides method for preparing amnion tissue grafts, as well as the grafts themselves. In specific embodiments, the tissue graft comprises a single layer of dried amnion from an umbilical cord. EP 4 66 3 21 1 A 3 Processed by Luminess, 75001 PARIS (FR) 2 EP 4 663 211 A3 5 10 15 20 25 30 35 40 45 50 55 3 EP 4 663 211 A3 5 10 15 20 25 30 35 40 45 50 55 4 EP 4 663 211 A3 5 10 15 20 25 30 35 40 45 50 55 5 EP 4 663 211 A3 5 10 15 20 25 30 35 40 45 50 55 摘要 CN Title 羊膜组织移植片及其制备和使用方法 CN Abstract 本发明提供了一种用于制备羊膜组织移植片的方法，以及该移植片本身。在特定实施例 中，该组织移植片包含来自脐带的单层干燥羊膜。

Claims

1. A method for preparing a dried amnion tissue graft from an umbilical cord, the method comprising the steps of: making a longitudinal cut in an amnion of the umbilical cord that has a lumen in order to expose contents of the lumen; removing, from the contents of the lumen, blood vessels and more than 50% of Wharton's jelly, but leaving some Wharton's jelly, to produce a debrided amnion; washing the debrided amnion; rinsing the washed amnion one or more times; and drying the rinsed amnion.

2. The method of claim 1, further comprising: incubating the debrided amnion before washing the debrided amnion.

3. The method of claim 1 or 2, wherein washing the amnion includes washing the amnion in a holding solution that comprises a buffer at pH of 6.5 to 7.0, and wherein the holding solution comprises: Tween-20: 0.5% (v / v); 0.05% (w / v) Polyhexamethylene biguanide hydrochloride; NaCl: 9 g / L; and a buffer at pH of 6.7 ± 0.1.

4. The method of any of claims 1 to 3, wherein the Wharton's jelly present in the umbilical cord amnion substantially or completely fills valleys between ridges on a surface of the debrided amnion.

5. The method of any of claims 1 to 4, wherein the step of washing is conducted for two to five hours and comprises agitation performed at 50 rotations per minute to 300 rotations per minute.

6. The method of any of claims 1 to 5, wherein the step of washing is conducted for three hours and comprises agitation performed at 100 rotations per minute to 200 rotations per minute.

7. The method of any of claims 1 to 6, wherein the step of rinsing the washed amnion includes rinsing the amnion in a rinsing solution that has a pH of 7.4 and comprises: NaCl: 7 to 10 g / L, anhydrous Na2HPO4: 0.5 to 1.5 g / L, and KH2PO4: 0.1 to 0.2 g / L.

8. The method of claim 7, wherein the rinsing solution comprises: NaCl: 9 g / L; anhydrous Na2HPO4: 0.795 g / L; and KH2PO4: 0.144 g / L.

9. The method of any of claims 1 to 8, wherein the step of rinsing is performed for three to five times in a rinsing solution, and wherein each rinsing step is performed for between 5 and 30 minutes at 50 rotations per minute to 300 rotations per minute.

10. The method of any of claims 1 to 9, wherein the debrided amnion is stored at 4°C before the washing step, or wherein the step of drying is performed for 15 hours under a pressure of between 15 and 50 mBar at a temperature of between 30°C and 40°C.

11. An amnion tissue graft comprising: a single membrane of umbilical cord amnion, wherein a smooth surface is created by Wharton's jelly, and wherein a thickness of the tissue graft does not vary by more than 20%.

12. The amnion tissue graft according to claim 11, wherein the amnion tissue graft is formed by removing, from the umbilical cord amnion, blood vessels and more than 50% of Wharton's jelly, but leaving some Wharton's jelly.

13. The amnion tissue graft according to claim 12, wherein Wharton's jelly substantially or completely fills valleys between ridges on a surface of the amnion to form the smooth surface.

14. The amnion tissue graft according to any of claims 11 to 13, further comprising an indicium that distinguishes the epithelial side of the amnion tissue graft from the stromal side of the amnion tissue graft; optionally, wherein the indicium is a protrusion out from a specified area of the amnion tissue graft; optionally, wherein the protrusion is designed to be suitable for being grasped by a forceps, and wherein the amnion tissue graft comprises rounded corners such that, when the amnion tissue graft is placed on a tissue or an organ, the amnion tissue graft is configured to conform and adhere to the tissue or the organ.

15. The amnion tissue graft according to any of claims 11 to 14, further comprising one or more bioactive compounds at similar levels of bioactive compounds as present in the amnion used to produce the tissue graft, wherein the one or more bioactive compounds include one or more of: interleukins, tissue inhibitors of metalloproteinases, epidermal growth factor, fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and transforming growth factor.

Images